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. 2023 Jun 7;18(6):e0286687. doi: 10.1371/journal.pone.0286687

Physiological mechanisms of muscle strength and power are dependent on the years post obtaining peak height velocity in elite juniors rowers: A cross-sectional study

Paulo Francisco de Almeida-Neto 1,2,*,#, Ayrton Bruno de Morais Ferreira 2,#, Adam Baxter-Jones 3, Jason Azevedo de Medeiros 1,2, Luiz Felipe da Silva 2, Paulo Moreira Silva Dantas 1,2, Breno Guilherme de Araújo Tinôco Cabral 1,2,*
Editor: Javier Abián-Vicén4
PMCID: PMC10246840  PMID: 37285362

Abstract

Background

It is not yet known whether the years after peak height velocity (PHV) are associated with the physiological mechanisms of muscle strength and power in Juniors rowers.

Objective

To identify the association between years post PHV (YPPHV) with muscle power and strength in Juniors rowers.

Methods

We tested 235 Brazilian rowing athletes (male: 171, female: 64, Juniors category). We measured: power (indoor rowing over 100-m, 500-m, 2,000-m and 6,000-m) and muscle strength (one repetition maximum (1RM) test in squat, deadlift, bench press and bent row on the bench). Biological maturation was index by age of PHV. The sample was divided into groups considering YPPHV recent (2.5 to 3.9), median (2.51 to 4.9) and veteran (>4.9). We use a Baysian approach to data handling.

Results

When compared to their peers in the recent and median post PHV groups, the male veteran group were superior in muscle power (Absolute: 100-m (BF10: 2893.85), 500-m (BF10: 553.77) and 6,000-m (BF10: 22.31). Relative: (100-m (BF10: 49.9)) and strength (BF10≥10.0 in squat, bench press and deadlift), and in the female the veteran group were superior in test time (500-m, BF10: 88.4).

Conclusion

In elite Juniors rowers the increasing YPPHV are associated with muscle power performance in both sexes and muscle strength performance in males.

Introduction

Rowing is a sport in which youth athletes start participating in sports competitions later than many other sport—competitors are usually between 16 and 18 years old when they are entered into the official competitive context. This fact increases the possibility that athletes are in advanced stages of biological maturation (BM), indexed by biological age (BA), because the chronological age range (CA) suggests the attainment of puberty influences performance post peak height velocity (PHV) [1]. BM is the phenomenon corresponding to the enhancement of the biological systems of the human body [2].

It is worth noting that, in relation to CA, BA can be classified as early, average or late [3]. One way to assess BA is by estimating the age that PHV is attained and then aligning individuals by a BA rather than CA. PHV is a measure that estimates the period in which the highest growth rate in height occurs during adolescence, the adolescent growth spurt [4]. Therefore, adolescent athletes who have already attained PHV (post-PHV) show superior performance than their peers who have not yet experienced (pre-PHV) or are currently experiencing (circum-PHV) this BM event [1, 5]. This is justified because the physiology of the PHV stages are distinct, with the late PHV stages showing more efficient physiological mechanisms in relation to their peers in the development process (pre- and circum-PHV) [6].

Theoretically, regardless of whether the PHV occurred early, average, or late, upon attaining PHV (BA between -1 and 1) the post-PHV stage (BA >1), performance differences between adolescent athletes should be minimized or zero. However, athletes in the early BM stage reached maturity fully first compared to their average and late maturity peers [7]. It is known, that in fully mature rowers, those who reached the Tanner V stage (i.e., final stage of sexual maturity) at a younger chronological age, continue to have higher lean mass and aerobic power than their peers who reached the same stage at an older chronological age [8].

Thus, it is possible that subjects who reached the post-PHV stage at a younger chronological age (early) continue to have advantages in physical performance compared to their peers who reached the same stage at an older chronological age. Previous studies have pointed out that reaching maturity (assessed by skeletal age and PHV) are associated with and influence increases aerobic and anaerobic strength and power performance in adolescent athletes [1, 9–11]. Given this conjecture, it is justifiable to verify the relationship of years after PHV (YPPHV) with strength and muscle power performance in rowers.

Analyzing the association of YPPHV may aid exercise prescription in pediatric sport, particularly during long-term athlete training. Recently research that seeks to understand the factors involved with exercise prescription for pediatric athletes in the short and long term has been encouraged [12]. This encouragement was grounded in the 2021 Olympic games (in Tokyo, Japan), where athletes aged 12, 13, and 14 years competed in table tennis, skateboarding, and swimming respectively [12].

Given such a perspective the objective of the present study is to identify association between years after obtaining, of PHV with specific performance characteristics in rowing and the performance of muscular strength of upper and lower limbs of both sexes of Brazilian Junior rowers. The present study hypotheses that increasing years after obtaining of PHV are related to the performance in Brazilian Juniors rowers of both sexes.

Methods

This is a cross-sectional study with a sample of 235 rowers (Brazilians, both sex, age: 17.0 ± 1.1, category Juniors). To determine the a priori sample size we made a calculation using the software G*Power (Version 3.0; Berlin, Germany) considering a standard α of 0.05, a β of 0.80 and the effect size (0.575) of a previous study [9] that evaluated the association between power in indoor rowing and maturation in rowers of both sexes in a post-PHV maturation stage. Thus, a minimum sample size of 18 subjects per group was indicated (power sample: 0.81).

To select participants for the present study, we used data available in an open-access database of the Brazilian Rowing Confederation (CBR) regarding the National Rowing Evaluation System (SNAR). The database contains information on anthropometrics (height, wingspan, and body weight), indoor rowing-specific tests (100-m, 500-m, 2,000-m, and 6,000-m), upper limb muscle strength tests (bent row on the bench and bench press), and lower limb muscle strength tests (squat and deadlift). These tests were performed annually on nationally ranked athletes.

Initially, we had access to information from 2,870 rowing athletes of both sexes and all categories. We screened athletes from the Junior category (up to 18 years of age 573 Junior rowers. To elect the participants for the present study, we considered for the final screening that the data should contain the following complete information: (i) Performance in indoor rowing of 100 m, 500 m, 2. 000 m, and 6,000 m. (ii) Rest and peak heart rate during performance at 100-m, 500-m, 2,000-m, and 6,000-m distance. (iii) Upper limb strength and lower limb strength. (iv) Height and body weight. 235 Junior rowers fulfilled these inclusion criteria (171 males and 64 females).

Study design

Twenty-four hours after the anthropometric evaluations, indoor rowing tests were performed in the following sequence: 100-m, 500-m, 2,000-m, and 6,000-m, with 24-hour intervals between tests. During the indoor rowing tests, exercise intensity was controlled by peak heart rate, which had to be > 80% of maximum heart rate. Forty-eight hours after the indoor rowing tests, muscle strength tests were performed in the following sequence: bench press, squat, bent row on the beach, and deadlift, with 24h intervals between tests.

We emphasize that we have contacted the CBR for information about the above procedures. Prior to all evaluations, athletes must perform a maximal stress test to determine their maximum heart rate and an echocardiogram examination to analyze the structure of the heart tissue. We emphasize that the CBR did not provide us with the results of these tests. Both tests were performed by a medical professional specializing in cardiology. Athletes can only participate in SNAR evaluations if they obtain verified medical authorization in writing. In the week after the medical clearance, the athletes were submitted to the tests mentioned above.

Ethics and registration

The present study used a public domain database, which exempts the present study from analysis by a local ethics committee. However, for ethical reasons we excluded from the database any information that could be used to identify any of the athletes (CBR registration, name, surname and location). And it is publicly available in the Open Science Framework Registries platform (Doi: 10.17605/OSF.IO/M8QR4). To structure the present research, we followed the recommendations of the STROBE reporting guide for observational studies [13].

Blinding

This study was blinded by the raters, the participating athletes, and the person responsible for data processing. The CBR raters were not aware of the present study when they collected the SNAR data and the athletes were not aware of the objectives of the present research. For data processing, the variable years post peak height velocity (YPPHV) was masked. Subsequently, the masked database was sent to a blinded researcher who had no prior access to the source data. Thus, the data analysis could not be manipulated to favor the initial hypothesis of the present study.

Procedures

Anthropometry

The anthropometric evaluations were performed with barefoot subjects wearing only light clothing, where their body mass was measured using a digital scale; for stature, the stadiometer was used; the wingspan was measured using an anthropometric tape. All evaluations were based on the International Society of the Advancement of Kinanthropometry (ISAK) protocol [14].

Years post peak height velocity

Attainment of peak height velocity (PHV) was estimated from anthropometric variables. Age from PHV attainment was predicted from mathematical regression models. Details about the models can be found in the study by Moore et al. [7]. In brief, using anthropometric values (height and weight) and CA of the individuals a BA was estimated, years from PHV, where PHV = between -1 and 1 indicated pre-PHV and BA > 1 indicated post-PHV. In the present sample all values of BA were post-PHV. Subsequently, to form similar BA groups (i.e., +1, +2 and so on), we used percentiles based on tertiles as follows: below tertile 33.33 were classified as recent post-PHV (up to 2.5 years for males and up to 3.99 years for females), between tertile 33. 33 and 66.67 were classified in median post-PHV (between 2.51 and 3.99 years for males and between 4.0 and 4.99 years for females), and above tertile 66.67 were classified as veteran post-PHV (above 3.39 years for males and above 4.99 years for females).

Heart rate

During sprint speed and specific performance assessments, the heart rate of the participants was assessed by short-range radio wave telemetry through a Polar®-type device (model unknown, Kempele, Finland) connected to a smartphone that was in the possession of the CBR assessor.

Sprint speed and specific performance

Before performing the physical tests, the participants performed a specific warm-up of 15 minutes of continuous indoor rowing at a self-selected intensity. Speed was analyzed by 100 m and 500 m maximal sprint tests. Specific performance was analyzed by 2,000 m and 6,000 m tests. All speed and specific performance tests were performed on an indoor rowing machine (Concept® model-D equipped with a PM5 digital monitor, Florida, USA). The tests were performed in an air-conditioned environment (26°C). For all analyses, the indoor rowing equipment was calibrated according to Australian International Rowing Federation specifications regarding predetermined resistance factors based on sex and age group for the Juniors category (Male: 120 (Ns2/m2). Female: 110 (Ns2/m2)) [15]. At the end of testing, test time results in seconds (100-m and 500-m) and minutes (2,000-m and 6,000-m) and power output in watts (all distances) were assimilated from the equipment by a computer attached to its PM5 digital monitor.

Upper and lower limb muscle strength

The analysis of muscle strength of the upper limbs (bent row on the bench and bench press) and lower limbs (squat and deadlift), considered the following protocol: (i) Initially, each athlete self-selected the load (Kg) that he/she considered adequate to perform one maximum repetition (1RM). (ii) Subsequently, after performing the exercise, the athlete informed his/her subjective perception of the load (in light, moderate and heavy). (iii) After informing his subjective perception, the CBR rater asked if he should adjust the load to a higher value; according to the athlete’s response, 3% of the load was increased or reduced. Each athlete had three attempts interspersed by five minutes of passive rest to perform 1RM, in all attempts the described procedure was repeated. When the athlete reached 1RM on the first or second repetition, the test was stopped and terminated. If the athlete could not perform the movement correctly with the initial relative load, the test was stopped and the athlete was given a 10-minute passive rest period to choose a lower subjective load and try again. Details of the equipment and techniques used in the strength tests can be found in S1 File.

Statistical analyses

Data normality was verified by Kolmogorov-Smirnov and Z-score tests for skewness and kurtosis (-1.96 to 1.96). Subsequently, we performed a Baysian ANOVA test, assuming, a priori, running the models on a comparative basis in the null model (no difference between groups). The Bayes factor (BF) was interpreted by magnitude [16]: 1 to 3.2: Not worth more than a bare mention, >3.2 to 10: substantial, >10 to 100: strong, >100: decisive. During the analyses, we used the YPPHV-based groups as fixed effect factors and the dependent variables were the indoor rowing performance and muscle strength test results. We made inference to a single model based on the posteriori estimates. Subsequently, when the alternative hypothesis (H1) was favored substantially or strongly we considered the pointed difference worthy of post-hoc (†) [16]. Thus, we checked the point differences between the post-PHV groups by Bayesian post-hoc analysis by the null control correction. In the a priori and a posteriori specification, numerical accuracy was set manually (at 10,000 No. sampling). We used a model with fixed and uniform effects. All analyses were performed in the open source software JASP® (Version 0.16.3.0; University of Amsterdam, Holland) as recommended by Wagenmakers et al. [17], considering the error rate of 5%.

Results

Table 1 shows the sample characterization. It can be seen that in males, the recent years from attainment of post-PHV (YPPHV) group had attained PHV two years previously, the median YPPHV group, were three years post PHV, and the veteran YPPHV group four years post PHV. In females, the recent YPPHV group had attained PHV two years previously, the median YPPHV group were t four and a half years post PHV, and the veteran YPPHV group were five and a half years post PHV. Thus, it can be observed descriptively, that subjects who were approximately 2 years post PHV (recent YPPHV) were smaller stature than their peers who were 4- or 5-years post PHV (veteran YPPHV), particularly in females. In addition, in both genders, the recent-YPPHV groups had lower body weights than their counterparts in the Median-YPPHV and Veteran-YPPHV groups. The standard error results of the performance measures are available in S2 File (Supplementary Table 1 (Table s-1)).

Table 1. Sample characterization.

Variables Male sex (n = 171) Female sex (n = 64)
YPPHV groups: Recent Median Veteran Recent Median Veteran
Participants number 58 56 57 22 24 18
Age (years) 16.1±0.8 17.1±0.7 18.0±0.5 15.5±0.9 17.2±0.6 18.0±0.6
PHV 2.0±0.5 3.0±0.3 4.0±0.4 3.1±0.6 4.6±0.3 5.5±0.4
Weight (Kg) 69.7±8.4 71.7±8.6 74.4±8.4 58.3±4.5 61.7±6.9 67.9±7.0
Stature (cm) 177.8±7.0 178.0±7.0 180.5±8.5 166.0±4.4 168.7±5.7 174.5±5.9
Wingspan (cm) 178.4±9.5 181.2±15.2 183.1±9.1 172.9±9.4 173.8±8.0 175.9±5.6
Resting heart rate (bpm) 60–9±1.1 58.8±0.8 57.0±0.8 60.2±1.6 57.1±0.8 55.6±0.9
100-m (sec) 19.1±8.6 20.6±14.1 17.0±0.8 32.8±3.2 20.5±1.0 19.2±0.8
500-m (sec) 97.2±7.1 94.9±5.6 95.1±10.0 113.1±6.8 109.1±6.6 104.3±5.6
2,000-m (min) 6.9±0.4 6.9±0.6 6.9±0.7 7.3±0.7 7.1±0.6 7.0±0.6
6,000-m (min) 21.4±2.2 21.1±1.8 20.6±2.0 21.6±2.7 21.4±2.5 22.5±2.2
100-m (Watts) 462.2±100.9 527.6±98.0 559.6±11.4 462.2±100.9 527.6±98.0 559.5±114.7
100-m (Watts/Kg) 6.6±1.3 7.3±0.9 7.5±1.2 5.6±0.7 5.4±0.8 5.7±0.7
500-m (Watts) 184.4±2.0 183.6±1.8 183.6±4.6 383.4±68.0 422.5±64.1 438.5±63.7
500-m (Watts/Kg) 5.5±1.0 5.9±0.8 5.8±0.5 4.9±1.1 5.1±1.1 4.8±0.7
2,000-m (Watts) 375.9±61.7 365.1±68.7 383.7±76.2 375.9±61.7 365.1±68.7 383.7±76.2
2,000 (Watts/Kg) 5.3±0.5 5.1±0.9 5.2±0.8 4.8±1.1 5.0±0.8 5.2±0.8
6,000-m (Watts) 272.4±72.0 290.2±73.0 325.0±84.7 272.4±72.0 290.2±73.0 325.0±84.7
6,000-m (Watts/Kg) 3.9±0.7 4.0±0.9 4.3±0.9 3.6±1.1 4.1±0.8 3.9±0.9
Peak heart rate in 100-m (bpm) 176.0±5.2 174.6±8.0 176.1±9.6 176.3±1.4 175.2±11.1 172.9±10.2
Peak heart rate in 500-m (bpm) 184.4±2.0 183.6±1.8 183.6±4.6 185.4±2.2 184.2±4.2 183.5±4.0
Peak heart rate in 2,000-m (bpm) 193.3±2.7 190.5±3.4 189.8±4.8 195.3±2.6 189.5±3.4 188.3±2.2
Peak heart rate in 6,000-m (bpm) 196.6±0.8 195.3±1.4 194.2±2.5 197.0±0.8 194.7±1.0 195.1±2.9
1RM in Bench press (Kg) 58.9±14.3 64.9±14.8 68.9±14.6 36.7±16.7 38.5±6.7 45.8±15.7
1RM in Rowing lyving down (Kg) 63.3±14.3 67.3±12.0 70.4±11.5 43.5±11.9 43.1±7.8 48.9±13.8
1RM in Squat (Kg) 85.0±19.8 100.6±22.3 104.1±23.3 64.3±18.8 66.2±13.9 79.8±33.6
1RM in Deadlift (Kg) 88.6±27.2 99.6±29.7 104.7±25.0 82.4±35.4 60.5±20.1 64.3±35.6
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n: Absolut number. YPPHV: Years post peak height velocity. PHV: Peak height velocity. Sec: Second’s. -m: meters. Min: Minutes. Bpm: beats per minute. Kg: kilograms. 1RM: One repetition maximum.

For males, the alternative hypothesis was favored with substantial or strong BF for absolute power produced during the 100-m, 500-m, and 6,000-m and for relative power in 100-m (See Table 2). In addition, the alternative hypothesis was favored for the 1RM tests in bench press, squat and deadlift. For females the alternative hypothesis was favored strongly only for the power produced during the 100-m test and the 500-m test time.

Table 2. Comparisons between the models.

Variable Models P (M) P(M|data) BFM BF10 Error (%)
Male Sex
100-m (sec) Null (H0) 0.50 0.75* 2.91 1.00
YPPHV (H1) 0.50 0.25 0.34 0.34 0.02
100-m (Watts) Null (H0) 0.50 0.00 0.00 1.00
YPPHV (H1) 0.50 1.00* 2893.85† 2893.85 0.03
100-m (Watts / Kg) Null (H0) 0.50 0.02 0.20 1.00
YPPHV (H1) 0.50 0.98* 49.9† 49.9 0.019
500-m (sec) Null (H0) 0.50 0.82* 4.75 1.00
YPPHV (H1) 0.50 0.17 0.21 0.21 0.02
500-m (Watts) Null (H0) 0.50 0.01 0.00 1.00
YPPHV (H1) 0.50 0.99* 553.77† 553.77 0.01
500-m (Watts / Kg) Null (H0) 0.50 0.49 0.99 1.00
YPPHV (H1) 0.50 0.51* 1.00 1.00 0.03
2,000-m (min) Null (H0) 0.50 0.93* 14.65 1.00
YPPHV (H1) 0.50 0.07 0.07 0.07 0.02
2,000-m (Watts) Null (H0) 0.50 0.88* 6.99 1.00
YPPHV (H1) 0.50 0.12 0.14 0.14 0.02
2,000-m (Watts / Kg) Null (H0) 0.50 0.76* 3.12 1.00
YPPHV (H1) 0.50 0.24 0.32 0.32 0.028
6,000-m (min) Null (H0) 0.50 0.73* 2.77 1.00
YPPHV (H1) 0.50 0.26 0.36 0.36 0.03
6,000-m (Watts) Null (H0) 0.50 0.04 0.05 1.00
YPPHV (H1) 0.50 0.96* 22.31† 22.31 0.03
6,000-m (Watts / Kg) Null (H0) 0.50 0.27 0.37 1.00
YPPHV (H1) 0.50 0.73* 2.69 2.69 0.04
1RM in Bench press (Kg) Null (H0) 0.50 0.05 0.05 1.00
YPPHV (H1) 0.50 0.95* 18.8† 18.8 0.03
1RM in Rowing lyving down (Kg) Null (H0) 0.50 0.27 0.37 1.00
YPPHV (H1) 0.50 0.73* 2.65 2.65 0.04
1RM in Squat (Kg) Null (H0) 0.50 0.01 0.00 1.00
YPPHV (H1) 0.50 0.99* 1987.55† 1987.5 0.01
1RM in Deadlift (Kg) Null (H0) 0.50 0.16 0.19 1.00
YPPHV (H1) 0.50 0.83* 5.07† 5.07 0.02
Female sex
100-m (sec) Null (H0) 0.50 0.38 0.62 1.00
YPPHV (H1) 0.50 0.61* 1.60 1.60 0.01
100-m (Watts) Null (H0) 0.50 0.08 0.09 1.00
YPPHV (H1) 0.50 0.91* 11.3† 11.3 0.01
100-m (Watts / Kg) Null (H0) 0.50 0.78* 3.66 1.00
YPPHV (H1) 0.50 0.22 0.27 0.27 0.033
500-m (sec) Null (H0) 0.50 0.01 0.01 1.00
YPPHV (H1) 0.50 0.99* 88.4† 88.4 0.006
500-m (Watts) Null (H0) 0.50 0.73* 2.72 1.00
YPPHV (H1) 0.50 0.26 0.36 0.36 0.04
500-m (Watts / Kg) Null (H0) 0.50 0.80* 3.89 1.00
YPPHV (H1) 0.50 0.20 0.25 0.25 0.03
2,000-m (min) Null (H0) 0.50 0.73* 2.80 1.00
YPPHV (H1) 0.50 0.26 0.35 0.35 0.03
2,000-m (Watts) Null (H0) 0.50 0.26 0.35 1.00
YPPHV (H1) 0.50 0.74* 2.81 2.81 0.01
2,000-m (Watts / Kg) Null (H0) 0.50 0.82* 4.57 1.00
YPPHV (H1) 0.50 0.18 0.21 0.21 0.032
6,000-m (min) Null (H0) 0.50 0.77 3.33 1.00
YPPHV (H1) 0.50 0.23 0.30 0.30 0.03
6,000-m (Watts) Null (H0) 0.50 0.43 0.76 1.00
YPPHV (H1) 0.50 0.56* 1.30 1.30 0.01
6,000-m (Watts / Kg) Null (H0) 0.50 0.67* 2.06 1.00
YPPHV (H1) 0.50 0.33 0.48 0.48 0.022
1RM in Bench press (Kg) Null (H0) 0.50 0.56* 1.29 1.00
YPPHV (H1) 0.50 0.43 0.77 0.77 0.02
1RM in Rowing lyving down (Kg) Null (H0) 0.50 0.70* 2.31 1.00
YPPHV (H1) 0.50 0.30 0.43 0.43 0.02
1RM in Squat (Kg) Null (H0) 0.50 0.52* 1.08 1.00
YPPHV (H1) 0.50 0.48 0.92 0.92 0.03
1RM in Deadlift (Kg) Null (H0) 0.50 0.40 0.70 1.00
YPPHV (H1) 0.50 0.60* 1.44 1.44 0.01
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YPPHV: Years post peak height velocity. -m: meters. Sec: Second’s. Min: Minutes. 1RM: One repetition maximum. Kg: kilograms. Model Null: contains the big average of the model. Model YPPHV: adds the effect of the years post the peak height velocity event occurred. P (M): Probability of the previous model. P(M|data): Updated probabilities after the observation of the data. BF: Bayes Factor. BFM: Individual Bayes Factor for each model. BF10: Bayes Factor for each line model relative to the null model (%): Percent. H0: Null Hypothesis. H1: Alternative Hypothesis.

*: Favored Hypothesis.

†: Post-hoc significance.

For males, in the power produced during the 100-m and 500-m test, post-hoc analyses showed that the veteran-YPPHV group (Absolute power in 100-m: BF10: 3703.0. In 500-m: BF10: 1026.8. Relative power in 100-m: F = BF10: 36.847) and median-YPPHV group (Absolute power in 100-m: BF10: 41.6. In 500-m: BF10: 15.7. Relative power in 100-m: F = BF10: 10.711) were superior to the recent-YPPHV group (See Fig 1A–1C). In the power output at 6,000-m the veteran-YPPHV group was superior to the recent-YPPHV group (BF10: 53.6) (See Fig 1D). For the 1RM bench press test the veteran-YPPHV group was superior to the recent-YPPHV group (BF10: 71.5) (See Fig 1E). For the 1 RM squat test the median-YPPHV (BF10: 159.2) and veteran-YPPHV (BF10: 2516.8) groups were superior to the recent-YPPHV group (See Fig 1F). For 1 RM in deadlift the veteran-YPPHV group was superior to the recent-YPPHV group (BF10: 23.1) (See Fig 1G).

Fig 1. Post hoc analysis of differences with substantial or strong magnitude.

Fig 1

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E (%): Error %. -m (meters). 1RM: One repetition maximum. Kg: kilograms. * Favor of the alternative hypothesis (H1).

In the female sample, the power produced during the 100-m test in the veteran-YPPHV group was superior to the recent-YPPHV (BF10: 10.1) and median-YPPHV (BF10: 6.4) groups (See Fig 1H). For the 500-m performance, the veteran-YPPHV group was superior to the median-YPPHV (BF10: 3.2) and recent-YPPHV (BF10: 246.5) groups (See Fig 1I).

Discussion

The purpose of the present study was to verify the association of years post PHV with the performance of Juniors category rowers. Thus, it was hypothesized that years after attainment of PHV would be associated with increased performance of Juniors rowers. Thus, the alternative hypothesis was accepted which found that athletes veteran post PHV athletes out performance superior their peers whose attainment of PHV was more recent.

Muscle power, biological maturation and rowing performance

In rowing, anaerobic muscle power is required during the performance of sports events, especially during the initial and final phases of the race, phases of high intensities (e.g., between 100 and 500-m) [18]. According to Moritani et al. [19] such a requirement can be justified by the recruitment of type II muscle fibers (i.e., glycolytic), i.e., the higher the intensity of exercise the greater the recruitment of this type of fiber which are responsible for the production of anaerobic muscle power. Han et al. [20] approach that type II muscle fibers have as one of their characteristics the high levels of the enzyme lactate dehydrogenase (LDH), which promotes the conversion of pyruvic acid into lactate, and the significant presence of the mATPease isoform hydrolyzes more molecules of Adenosine triphosphate (ATP) than type I fibers (i.e., oxidative).

In the initial phase of the rowing race (i.e., first 500-m), due to the accumulation of hydrogen ions and the drop in intramuscular pH, there is a reduction in the activity of glycolytic enzymes (e.g., phosphofructokinase), which leads to a reduction in the anaerobic power exerted by athletes [21]. Due to this, athletes are forced to reduce the rate of strokes, thus, the production of cellular energy by anaerobic pathways is significantly reduced, and the aerobic system becomes predominant (i.e., between 65% and 75%) [18, 22]. During this process recovery of the phosphagenic system through resynthesis of phosphocreatine will occur [23]. This contributes to the final phase of the rowing race (i.e., last 100-m to 300-m), which according to Held, Siebert & Donath [24] is where increased stroke rates occur and anaerobic metabolism becomes predominant again in cellular energy production.

In a longitudinal study that analyzed elite rowers of both sexes from the Juniors category, Almeida-Neto et al. [10] found that the advancement of biological maturation (BM) influenced the increase in power during performance in indoor rowing and in boat. Regarding muscle tissue, subjects in late BM stages point to a higher percentage of type I muscle fibers, presenting high levels of mitochondrial density and oxidative enzyme activity [25–29]. In this sense, late-stage athletes are disadvantaged due to lower concentration of anaerobic enzymes, such as LDH, Creatine kinase (CK) and Adenylate kinase (AK) compared to their early-stage peers, who have high levels of said enzymes [6, 30].

Given this, it is expected that when reaching the final BM stage, physiological differences are balanced among adolescent athletes [1, 6]. However, previously the study conducted by Mikulic [8], followed for five years male rowers aged 12–13 years, with 10 maturing early and nine maturing late. The study analyzed sexual maturation by Tanner stages, lean body mass by anthropometry, Vo2MAX by maximal effort test performed on a treadmill, and average power by wingate test performed in indoor rowing. The primary endpoint of the study found that after five years of follow-up, the advantage of early maturers decreased in terms of lean body mass (+38% to +9%), Vo2MAX (+47% to +9%), and average power (+76% to +15%). However, although the final stage of sexual maturation was the same (post-pubertal), the subjects who reached the final stage of maturation early still had advantages over those who reached late, corroborating the present study.

Regarding the production of muscle power, Kaczor et al. [30] identified that the advancement of chronological age (CA) is determinant for the increase of anaerobic enzymes (e.g., LDH, CK and AK) and, consequently, the improvement of the efficiency of cellular energy production by anaerobic pathways. Considering the study by Benjamin [31] who found that the pace of aging is determined by biological age (BA) rather than chronological age, and the works of Malina & Bouchard [1] and Rowland [6] who detail the physiological particularities of the stages of BM in relation to CA, we can conjecture that BM is a marker of BA. Therefore, it is possible to state that subjects who reach the final stage of BM early have advanced BA compared to their peers of the same CA who reached the final stage of BM late. This thought may explain the results found by the present study regarding muscle power and years post PHV.

Muscle strength, biological maturation and rowing performance

Rowing is a sport that interacts directly with the aquatic environment. Thus, the muscular strength exerted by the rower against water resistance is a constant reality of the sport in question [9]. Thus, muscular strength of the upper limbs, lower limbs, and trunk are directly related to the performance of rowers [32–34]. Furthermore, maturational stages have been shown to be related to strength in males, with strength gains being greater during and after PHV when compared to the pre-PHV phase [35].

This is corroborated in the present study, where individuals who were BA older (i.e. were further from attainment of PHV) (YPPHV-Veteran) performed better in the strength tests (squat, supine, and deadlift) than younger BA maturing peers (recent and median YPPHV). A possible explanation for this finding is due to the stretching-shortening cycle (SSC), which is characterized by an eccentric stretching action before a subsequent concentric shortening action [36]. SSC improves its efficiency with age. Thus, changes in the neuromuscular system during growth and maturation include increases in muscle size [11], pennation angle [37], fascicle length [38], tendon stiffness [39], motor unit recruitment[40], and preactivation [41]. These adaptations result in improved SSC performance due to elastic energy reuse, neural potentiation, and an enhanced stretch reflex contribution, mainly due to an increase in force production capabilities [42]. According to the findings of the present study, after attaining PHV the apparent residual effects of superiority in muscle strength of the BA older YPPHV-veteran group, who reached the post-PHV stage first than their peers in the YPPHV-recent and YPPHV-median groups.

In females, however, there was no difference in the performance of strength tests between the groups. It is known that adaptations in strength differ between the sexes, mainly due to differences in circulating anabolic hormones, which are higher in boys than in girls from puberty and which directly influence the increase in muscle mass [43, 44]. The literature points out that boys gain about 7.2 kg of muscle mass per year during PHV, while girls gain only 3.5 kg per year [45]. Furthermore, PHV in females occurs on average two years earlier than in males; however, muscle mass gains decrease in girls from the age of 15, while in boys, these gains extend until the age of 20 [45]. Such a fact may explain why YPPHV-veteran female athletes show no difference in strength levels compared to their YPPHV-recent and YPPHV-median peers.

Biological maturation, body weight and performance in rowers

Currently in rowing, competitive categories for ages >18 years are divided by body weight (lightweights & heavyweights), however, for junior categories (ages = <18 years) this body weight criterion is not considered [15], which may contribute to a physical discrepancy among adolescent athletes. Thus, it is feasible to think of strategies that may balance the differences between recent-YPPHV athletes and their median-YPPHV and veteran-YPPHV peers.

It is known that during the maturation process the gain of lean mass, power and muscle strength are greater in athletes who mature early [1, 6]. Previously it has been pointed out that rowers who reached full maturation late point out smaller size and body weight compared to their peers who reached full maturation early [8]. This suggests that the residual effect of early PHV attainment may favor body weight gain in median-YPPHV and veteran-YPPHV rowers.

Based on this assumption, the body weight can help rowers to perform a "lever" to increase the drag of the boat in the liquid environment. Considering that at the end of the "rowing act" there is synchronous extension of the ankles, knees, hips, and trunk respectively. Thus, the body weight is "thrown" back toward the bow of the boat, which can increase the speed of the boat. Thus, when prescribing training for junior rowers it is interesting to consider body weight as a determining variable for performance.

Conjectures regarding the relationship of YPPHV to strength and power

The present study is a pioneer in looking at the relationship of YPPHV is reached to muscle strength and power in rowers. Information on the relationship or effect of reaching maturity at a younger or older chronological age is scarce. Thus, the present study conjectures that because neurophysiological maturation about strength and muscle power occurs earlier in subjects who reached biological maturity at a younger chronological age this lasts into early adulthood (18 years) compared to subjects who reached biological maturity at an older chronological age. However, this is only conjecture and more investigations are needed on the tematic.

Limitations and suggestions for new studies

The main limitation of the present study is that we used an observational design, which made it impossible for us to prove the effect of BA on the strength and muscle power of elite rowers of both sexes in the Juniors category. We were also not able to define the individuals timing of PHV (i.e. early, average or late) We suggest that new studies should longitudinally follow rowing athletes from the pre-PHV biological maturation stage to the post-PHV stage, subsequently following post-PHV BA categories until the full adult maturity is reached. In this way we will have a more concrete answer about the existence of the effect of years from attainment of PHV. We also suggest that future research analyze the relationship of years from attainment of PHV with strength and muscle power in adolescents who do not participate in sports, so that we can verify if the gain in strength and muscle power in adolescents is related to aspects of biological maturation or training time.

Conclusion

It is concluded that in elite Juniors rowers the increasing years post PHV attainment are associated with improved muscle power performance in both sexes and muscle strength performance in males, suggesting that the residual effects of early maturation in relation to strength and muscle power advantage still persist until the age of 18 in rowers of both sexes (between four and six years post the PHV).

As a practical application, we suggest that rowing coaches divide the Juniors category teams according to BA (years from PHV). Afterwards, plan the training of the athletes considering the years from attainment of PHV, emphasizing strength training for male athletes classified in recent-YPPHV (e.g., BA +2) and median-YPPHV (e.g., BA +3), and for power training for athletes of both sexes classified in recent-YPPHV (e.g., BA +2) and median-YPPHV (e.g., BA +3). We also suggest that nutritional interventions be performed considering YPPHV, where athletes who point recent YPPHV need a diet that enhances lean mass and body weight gain, this may help offset the body weight difference compared to their peers with median and veteran YPPHV. We hope that in this way the level of the team will be equalized.

Supporting information

S1 File. Details of the equipment and techniques used in the strength tests.

(PDF)

Click here for additional data file. (170.3KB, pdf)
S2 File. Standard error results of the performance measures are available.

(DOCX)

Click here for additional data file. (19KB, docx)
S3 File

(PDF)

Click here for additional data file. (102.8KB, pdf)

Acknowledgments

For your support and encouragement for the development of this academic article, we thank the Federal University of Rio Grande do Norte (UFRN), the Physical Activity and Health (AFISA) research base, the Child and Adolescent Maturation Research Group (GEPMAC). The National Council for Scientific Development (CNPQ) and the Higher Education Personnel Improvement Coordination (CAPES). For the support during the production of this study we thank the researchers Matheus Dantas (ORCID: 0000-0002-1815-2251) and Radamés Medeiros (ORCID: 0000-0003-0811-2851).

Data Availability

The database for this study is publicly available at: https://figshare.com, under the Doi: 10.6084/m9.figshare.21528798. Supplementary file 1 is publicly available at: https://figshare.com, under the Doi: 10.6084/m9.figshare.21528831. The full public access database can be found on the CBR website (https://www.remobrasil.com/bole-tins/boletins-tecnicos). The protocol of this study is available at: https://archive.org/details/osf-registrations-m8qr4-v1.

Funding Statement

The author(s) received no specific funding for this work.

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Decision Letter 0

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30 Mar 2023

PONE-D-23-05680Physiological mechanisms of muscle strength and power are dependent on the years post obtaining Peak Height Velocity in elite Juniors rowers?PLOS ONE

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Reviewer #1: Thank you for the opportunity to review this manuscript. The research is interesting in principle. However, the manuscript is difficult to follow in parts. Especially the results are presented in an unclear way. Also the discussion seems to be a bit vague. This should definitely be revised. In addition, the visual abstract is not comprehensible in its current state. The methodology should also be revised: Were 100, 500, 2000 and 6000 tests completed on the same day? more informant about the maximal stress test is needed! please add reliability data for the concept 2 erg and testing procedure! Same for the strength testing procedure. How were the strength tests standardized? The results show that the body mass increases from recent to median to veteran. This must be taken into account in the power data. Eventually the differences found will disappear. In the figures, consistently indicate either watts or pace. Based on these points, I recommend a comprehensive revision of the manuscript.

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Submitted filename: PONE-D-23-05680v1.doc

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PLoS One. 2023 Jun 7;18(6):e0286687. doi: 10.1371/journal.pone.0286687.r002

Author response to Decision Letter 0

4 Apr 2023

Response to reviews

Manuscript title:

PONE-D-23-05680- Physiological mechanisms of muscle strength and power are dependent on the years post obtaining Peak Height Velocity in elite Juniors rowers?

Reviewer #1:

1) Thank you for the opportunity to review this manuscript. The research is interesting in principle. However, the manuscript is difficult to follow in parts. Especially the results are presented in an unclear way. Also the discussion seems to be a bit vague. This should definitely be revised.

Answer:

We reviewed the results, they were reported as described by the study by Wagenmakers et al., (2018, DOI: 10.3758/s13423-017-1323-7), the authors address how to use the Baysian approach. In addition, we present in the figures only those results worthy of post-hoc, as suggested by Kass & Raftery (1995, DOI: 10.2307/2291091).

Regarding discussion, we stress that our study is the first to address the relationship of years after PHV attainment with muscle strength and power. Previous studies address the influence of PHV and other biological maturation events (bone age, sexual maturation, expected height as an adult, etc.). Only one study that looked at rowers from pre-puberty to post-puberty addressed that after all subjects reached sexual maturation completely, rowing athletes who reached sexual maturity at a younger chronological age continued to have advantages over those who reached sexual maturity at an older chronological age (DOI: 0.1111/j.1600-0838.2010. 01200.x), we cite this study in our discussion (line 328 to 338).

In light of this, our discussion addressed the mechanisms involved with gains in muscular power and strength in relation to the characteristics of the stages of biological maturity, where the more mature the subject is the higher the levels of strength and muscular power. As pointed out in our introduction (line 94 to 96), when reaching full maturity, the differences in strength and muscle power should not be significant among mature athletes, but our study found that the advantages last until the age of 18! This may be justified because the body has had more time (biologically speaking) to adapt to the physiological changes resulting from the maturation process, we have inserted a brief topic in our discussion exposing this conjecture (line 381 to 389).

2) In addition, the visual abstract is not comprehensible in its current state.

Answer:

Upon the reviewer's report we adjusted the visual abstract as described by Ibrahim et al., (2017; DOI: 10.1097/SLA.0000000000002277).

3) The methodology should also be revised: Were 100, 500, 2000 and 6000 tests completed on the same day?

Answer:

We appreciate the reviewer's observation, there was a typo in the study design session, we have adjusted and identified the "washout" time between tests (line 144 to 151).

4) more informant about the maximal stress test is needed! please add reliability data for the concept 2 erg and testing procedure!

Answer:

Concept 2 is a valid device, we point out that the data are from the Brazilian rowing confederation as described in the manuscript (line 129 to 135 & 152 to 159), so we did not have access to the evaluations, only the final results, and we do not have test and retest data to infer reliability. However, we entered the standard error of the evaluations from the manuscript in a supplementary file (supplementary file 2).

In addition, we point out that previously Smith & Hopkins (2012, Doi: https://doi.org/10.2165/11597230-000000000-00000), reported that well-trained rowers have a typical error in time performance of only ~0.5% between repeated 2000m attempts on this ergometer. Similarly, Almeida-Neto et al., (2020, https://doi.org/10.1371/journal.pone.0243157) found that for post-PHV maturing rowers, the rowing ergometer points to good reliability with performance in water (ICC = 0,897; IC 95% = [0,737; 0,962]).

Therefore, it is reliable and appropriate to use the concept II to track changes in physiological performance and factors affecting it, and considering that the sample is of elite national-level athletes and that the evaluations were performed by trained assessors trained by the Brazilian Rowing Confederation, the results of our study are reliable.

5) Same for the strength testing procedure. How were the strength tests standardized?

Answer:

The strength tests were standardized according to the Brazilian Rowing Confederation, we inserted a supplementary file with the details of the 1RM evaluations (Supplementary file 1).

6) The results show that the body mass increases from recent to median to veteran. This must be taken into account in the power data. Eventually the differences found will disappear. In the figures, consistently indicate either watts or pace. Based on these points, I recommend a comprehensive revision of the manuscript.

Answer:

Thanks to the reviewer's remark, we have inserted analyses of the relative power (Watts/kg) (table 2), and only the differences for 100-m (male sex) remain (figure 1B).

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Reviewer #2:

General comments: As per notes attached, Some adaptations in the introduction, such as better identification of the problem, and in the methodology, such as a better description of the sample size, are necessary. It should still be considered to improve the conclusions and update the theoretical framework.

1) Title: Are presented satisfactorily.

Answer: ok.

2) Abstract: Are presented satisfactorily. I suggest adding some absolute and statistical results to help visualize the work.

Answer: We insert numerical results (Bayes Factor) in the results section of the summary (line 64 to 67).

3) Keywords: Please confirm that the keywords appear as descriptors in health sciences.

Answer: We adjust the keywords as requested.

4) Introduction: It should initially present a more general approach, gradually address the problem (gap), and then present the objective. The problem must be better identified. Mentioning that PHV and its relationship to what the study proposes is still unclear would not be a problem. I suggest continuing with the statements for and against the aforementioned so that we can naturally trigger the objectives.

Answer: We adjusted the introduction to expose the problem in a more appropriate way (line 98 a 108).

5) Methods: It should present the design of the study. A CONSORT or timeline should be presented in order to get a better view of the study design.

Answer: Our study complies with the STROBE chekinlist for observational studies (line 165 to 167).

6) The sample should be better explained with the number of subjects presented initially and then present the inclusion and exclusion criteria. As it was determined that 235 junior rowers (171 men and 64 women) would be needed or sufficient. please clarify.

Answer: We insert the description of the sample calculation in the methods (line 123 to 128).

7) Results: Are presented satisfactorily.

Answer: ok.

8) Discussion: Are presented satisfactorily.

Answer: ok.

9) Conclusion: Are presented satisfactorily. However, it would be necessary to present the practical applications of the results found.

Answer: We insert the practical applicability’s in the conclusion (line 408 to 414).

10) References: Are presented satisfactorily. However, of the 45 references, only 15 are current and 30 have more than five years of publication. Please update the theoretical framework.

Answer: We tried to update the references, but could not! we hope that the reviewer understands that the theme of the study has not been widely addressed in the literature. The only study similar to the theme was published in 2010 (DOI: 0.1111/j.1600-0838.2010. 01200.x), in relation to the studies about the rowing characteristics, muscle fiber types in children and about anaerobic and aerobic enzymes we cited the original studies, when we tried to update with current studies, they did not contemplate what we need to replace the reference.

Attachment

Submitted filename: Responses to reviews PONE-D-23-05680v1.doc

Click here for additional data file. (45KB, doc)

Decision Letter 1

Javier Abián-Vicén

15 May 2023

PONE-D-23-05680R1Physiological mechanisms of muscle strength and power are dependent on the years post obtaining Peak Height Velocity in elite Juniors rowers:  A cross-sectional studyPLOS ONE

Dear Dr. Almeida-Neto,

Thank you for submitting your manuscript to PLOS ONE. After careful consideration, we feel that it has merit but does not fully meet PLOS ONE’s publication criteria as it currently stands. Therefore, we invite you to submit a revised version of the manuscript that addresses the points raised during the review process.

==============================

ACADEMIC EDITOR:Thank you for the new version of your paper. The authors must respond to the comments and requirements of reviewer one for the paper to be finally accepted.

==============================

Please submit your revised manuscript by Jun 29 2023 11:59PM. If you will need more time than this to complete your revisions, please reply to this message or contact the journal office at plosone@plos.org. When you're ready to submit your revision, log on to https://www.editorialmanager.com/pone/ and select the 'Submissions Needing Revision' folder to locate your manuscript file.

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Academic Editor

PLOS ONE

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Reviewers' comments:

Reviewer's Responses to Questions

Comments to the Author

1. If the authors have adequately addressed your comments raised in a previous round of review and you feel that this manuscript is now acceptable for publication, you may indicate that here to bypass the “Comments to the Author” section, enter your conflict of interest statement in the “Confidential to Editor” section, and submit your "Accept" recommendation.

Reviewer #1: All comments have been addressed

Reviewer #3: All comments have been addressed

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2. Is the manuscript technically sound, and do the data support the conclusions?

The manuscript must describe a technically sound piece of scientific research with data that supports the conclusions. Experiments must have been conducted rigorously, with appropriate controls, replication, and sample sizes. The conclusions must be drawn appropriately based on the data presented.

Reviewer #1: Partly

Reviewer #3: Yes

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3. Has the statistical analysis been performed appropriately and rigorously?

Reviewer #1: Yes

Reviewer #3: Yes

********** 

4. Have the authors made all data underlying the findings in their manuscript fully available?

The PLOS Data policy requires authors to make all data underlying the findings described in their manuscript fully available without restriction, with rare exception (please refer to the Data Availability Statement in the manuscript PDF file). The data should be provided as part of the manuscript or its supporting information, or deposited to a public repository. For example, in addition to summary statistics, the data points behind means, medians and variance measures should be available. If there are restrictions on publicly sharing data—e.g. participant privacy or use of data from a third party—those must be specified.

Reviewer #1: Yes

Reviewer #3: Yes

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Reviewer #1: Yes

Reviewer #3: Yes

********** 

6. Review Comments to the Author

Please use the space provided to explain your answers to the questions above. You may also include additional comments for the author, including concerns about dual publication, research ethics, or publication ethics. (Please upload your review as an attachment if it exceeds 20,000 characters)

Reviewer #1: Thank you for this revision. All of the points I raised have been adequately addressed. However, it is now the case that when the results are considered relative to mass, only the differences for 100m performance are relevant. Even when viewed in absolute terms, there is significant overlap in the results, including in the 100m test performances. This raises the question of why trainers and coaches need to consider peak height velocity/maturation at all. The results seem to show a strong overlap, suggesting that these factors may not be as relevant as previously thought.

Overall, the interpretation of the results and the discussion should focus more on the implications of these findings for trainers and athletes. Why is it not sufficient to simply consider biological age? Combining biological age and mass, for example, could already explain a large portion of the variance in performance. These aspects should definitely be added or highlighted more prominently in the revised version.

Reviewer #3: Dear authors,

Congratulations for your work. Your revision has improved the quality of the document and it is now ready for acceptance.

********** 

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Reviewer #1: No

Reviewer #3: No

**********

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PLoS One. 2023 Jun 7;18(6):e0286687. doi: 10.1371/journal.pone.0286687.r004

Author response to Decision Letter 1

16 May 2023

Reviewer #1:

Thank you for this revision. All of the points I raised have been adequately addressed. However, it is now the case that when the results are considered relative to mass, only the differences for 100m performance are relevant. Even when viewed in absolute terms, there is significant overlap in the results, including in the 100m test performances. This raises the question of why trainers and coaches need to consider peak height velocity/maturation at all. The results seem to show a strong overlap, suggesting that these factors may not be as relevant as previously thought.

Overall, the interpretation of the results and the discussion should focus more on the implications of these findings for trainers and athletes. Why is it not sufficient to simply consider biological age? Combining biological age and mass, for example, could already explain a large portion of the variance in performance. These aspects should definitely be added or highlighted more prominently in the revised version.

Answer: In the results section, in the description of Table 1, we address the difference in body weight between the groups (lines 256 to 258). In addition, in the discussion session we inserted a topic on “Biological maturation, body weight and performance in rowers” (lines 384 to 402). Finally, in the concluding section, we gave a suggestion of practical applicability aimed at nutritional intervention to increase body weight in recent-YPPHV athletes (lines 436 to 440).

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Reviewer #3:

Dear authors, congratulations for your work. Your revision has improved the quality of the document and it is now ready for acceptance.

Answer: Thanks’.

Attachment

Submitted filename: R2 - Responses to reviews PONE-D-23-05680v1.doc

Click here for additional data file. (33.5KB, doc)

Decision Letter 2

Javier Abián-Vicén

22 May 2023

Physiological mechanisms of muscle strength and power are dependent on the years post obtaining Peak Height Velocity in elite Juniors rowers:  A cross-sectional study

PONE-D-23-05680R2

Dear Dr. Almeida-Neto,

We’re pleased to inform you that your manuscript has been judged scientifically suitable for publication and will be formally accepted for publication once it meets all outstanding technical requirements.

Within one week, you’ll receive an e-mail detailing the required amendments. When these have been addressed, you’ll receive a formal acceptance letter and your manuscript will be scheduled for publication.

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Kind regards,

Javier Abián-Vicén, Ph.D.

Academic Editor

PLOS ONE

Additional Editor Comments (optional):

Congratulations for your work!, I consider that your paper can be published in its current form.

Reviewers' comments:

Acceptance letter

Javier Abián-Vicén

26 May 2023

PONE-D-23-05680R2

Physiological mechanisms of muscle strength and power are dependent on the years post obtaining Peak Height Velocity in elite Juniors rowers:  A cross-sectional study

Dear Dr. Almeida-Neto:

I'm pleased to inform you that your manuscript has been deemed suitable for publication in PLOS ONE. Congratulations! Your manuscript is now with our production department.

If your institution or institutions have a press office, please let them know about your upcoming paper now to help maximize its impact. If they'll be preparing press materials, please inform our press team within the next 48 hours. Your manuscript will remain under strict press embargo until 2 pm Eastern Time on the date of publication. For more information please contact onepress@plos.org.

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Kind regards,

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on behalf of

Dr. Javier Abián-Vicén

Academic Editor

PLOS ONE

Associated Data

    This section collects any data citations, data availability statements, or supplementary materials included in this article.

    Supplementary Materials

    S1 File. Details of the equipment and techniques used in the strength tests.

    (PDF)

    Click here for additional data file. (170.3KB, pdf)
    S2 File. Standard error results of the performance measures are available.

    (DOCX)

    Click here for additional data file. (19KB, docx)
    S3 File

    (PDF)

    Click here for additional data file. (102.8KB, pdf)
    Attachment

    Submitted filename: PONE-D-23-05680v1.doc

    Click here for additional data file. (47KB, doc)
    Attachment

    Submitted filename: Responses to reviews PONE-D-23-05680v1.doc

    Click here for additional data file. (45KB, doc)
    Attachment

    Submitted filename: R2 - Responses to reviews PONE-D-23-05680v1.doc

    Click here for additional data file. (33.5KB, doc)

    Data Availability Statement

    The database for this study is publicly available at: https://figshare.com, under the Doi: 10.6084/m9.figshare.21528798. Supplementary file 1 is publicly available at: https://figshare.com, under the Doi: 10.6084/m9.figshare.21528831. The full public access database can be found on the CBR website (https://www.remobrasil.com/bole-tins/boletins-tecnicos). The protocol of this study is available at: https://archive.org/details/osf-registrations-m8qr4-v1.

    Articles from PLOS ONE are provided here courtesy of PLOS

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