The role of body composition on cardio-respiratory fitness in futsal competitive athletes

Abstract

Futsal is an intermittent high intensity sport which has become popular worldwide. Body composition and physical fitness have been studied in different sports disciplines. However, little is known regarding body composition and cardio-respiratory performance in competitive futsal players. Body composition parameters were analyzed by electrical impedance body composition analyzer in 31 competitive male futsal players. All participants performed spirometry, handgrip strength and cardiopulmonary exercise testing. Significant correlations were observed between muscle mass and spirometry parameters and peak VO2 (p≤0.05). Fat mass resulted inversely correlated with peak VO2% predicted and hand grip strength (p≤0.05). Regression analysis showed that muscle mass significantly predicts respiratory parameters (p<0.01) and reduced fat mass is associated with increased peak VO2 % predicted and handgrip strength (p<0.01). In futsal competitive athletes increased muscle mass is associated with higher spirometry parameters and fat mass is inversely associated with lower cardiorespiratory fitness.

Ethical Publication Statement

We confirm that we have read the Journal’s position on issues involved in ethical publication and affirm that this report is consistent with those guidelines.

Futsal is a five-a-side indoor soccer officially authorized by International Association Football Federation (FIFA), which has been played for more than 80 years and has become popular worldwide.¹ Futsal is played within professional, semi-professional and amateur level in a 40 x 20 m court, with 3x2 m goal posts, 4 outfield players and 1 goalkeeper. A futsal match is organized in 2 halves of 20 minutes, separated by a 10-minute break. During match-play 1-minute time-out in each half may be requested by the teams. In competitions the squad consist of a maximum of 14 players and a number of unlimited substitutions are permitted. Futsal is an intermittent high intensity sport and the physiological demands during competitions are high: about 80% of maximum oxygen uptake (VO2 max) and more than 85% of maximal heart rate.² It has been reported that in elite futsal players mean values of VO2 uptake as measured by a portable gas analyzer reach up to 62.9 ml/kg/min. Compared to professional players, semi-professional futsal players have a significant lower VO2 max 55.2 vs 62.8 ml/kg/min, but with minimal difference in VO2 at the ventilatory threshold (VT) expressed as percentage of VO2 max.³ High number of matches during a season and high intensity movements as sprinting and trackling activate the anaerobic component and may explain the above-mentioned findings. According to different studies,^4,5 futsal players do not display significant differences regarding body composition and anthropometric characteristics as compared to the competitive level. Indeed, similar fat mass has been described in elite and sub-elite futsal players, but with differences in lean mass between dominant and non-dominant legs. In contrast, compared to elite soccer players a higher body fat percentage has been described among futsal elite players.⁶ It has been reported that respiratory parameters, measured by spirometry are significantly higher in elite athletes compared to general population regardless of age.^7,8 Forced vital capacity (FVC) resulted higher in all sports disciplines compared to references values and forced expiratory volume in the 1st second (FEV1) was higher among ball games athletes.⁹ Another study reported that futsal players presented lower FEV1 and FVC compared to soccer athletes.¹⁰ Furthermore, it has been suggested that muscle mass is positively associated with both FEV1 and FVC in athletes and body composition may be helpful in monitoring respiratory function.¹¹ However, little is known regarding body composition and cardio-respiratory performance in competitive futsal athletes.

In this study we aimed to describe the relationship between body composition parameters and cardiorespiratory performance in competitive futsal male athletes.

Materials and Methods

In this study competitive futsal athletes undergoing medical check-up and clinical evaluation in Exercise and Sports Medicine Unit “Antonio Cardarelli Hospital”, Department of Medicine and Health Sciences, University of Molise, Italy, from January 2019 to December 2020 were considered for enrollment. Competitive athletes are defined as individuals training at least 5 h per week being regularly involved in competitions.¹² The clinical evaluation of athletes consists on anamnestic information regarding cardiovascular risk factors, comorbidities and medications, body composition measurements, spirometry, exercise stress testing or cardiopulmonary exercise testing (CPET). Athletes participating in this study were included if the following inclusion criteria were met: a) age ≥ 16 years, b) no injuries in the three months prior to the clinical evaluation c) taking no dietary supplements for improving muscle mass, and d) the absence of medical conditions, or medications which could influence respiratory function. Data from athletes which performed treadmill exercise testing instead of CPET were not considered for this study. All participants or their legal representative in the case of athletes of age younger than 18 years, provided informed written consent for anonymous data collection prior to the study.

All procedures were approved by the Institutional Review Board of Department of Medicine and Health Sciences, University of Molise, Italy and conducted in accordance with the declaration of Helsinki for studies on humans.

Height was measured with a stadiometer (Wunder SA. Bl. srl A 200), bare feet in standing upright position. Body mass, fat-free mass, muscle mass, percentage of muscle mass, fat mass, percentage of fat mass, and BMI were estimated via the electrical impedance body composition analyzer foot to foot TANITA BC-420MA (Tanita Corporation, Tokyo, Japan), as indicated by the manufacturer.

Lung function was measured by maximum flow- volume loops using a spirometer (Sensormedics Viasys Carefusion Vmax Encore 22). Spirometry was performed, with the subjects seated, wearing a nose clip, on the same after body composition measurements. All measurements and maneuvers were performed based on recommended standard.¹³ Forced vital capacity (FVC), forced expiratory volume in the first second (FEV1), and FEV1/FVC were measured and recorded as actual values and percent of predicted.

Hand grip strength was evaluated with handheld dynamometer DynX (MD Systems, Inc, Ohio, USA). Measurements were performed as described elsewhere.¹⁴ In brief, the participant in a seating position performed a maximal effort for three times both in the right and left sides. Participants were asked to squeeze maximally for 5 seconds and the higher average of the two sides was assigned dominance. The mean result of three measurements from the dominant side was recorded in kilograms (Kg).

Respiratory gas exchange measurements and physical performance parameters were obtained by the use of a treadmill Cosmed T150med, a two-way breathing Hans Rudolph 7450 series V2 mask and headgear applied on the subject. The exercise stress on treadmill test started with 8 km/h speed and continuing with stepwise increases of 1 km/h every minute. After reaching a speed of 14 km/h, the treadmill inclination was increased by 1% every minute. For all subjects was required continuous electrocardiogram (ECG) monitoring using a 12 lead ECG recording system Quark T12X wireless12-lead and frequent arterial blood pressure measurements during exercise. All participants were encouraged to exercise until exhaustion. The test finished when one of the following conditions were met: Rate of Perceived Exertion > 8; Failure of oxygen uptake or heart rate (HR) due to additional increase in work rate. Peak respiratory exchange ratio (RER) ≥ 1.04.

Descriptive data are presented as mean and standard deviation (SD), or number and percentage. Shapiro-Wilk test was performed to evaluate the normality of data distribution. Population was divided in age tertiles and one-way ANOVA analysis was performed. Correlations between variables of interest were evaluated by Pearson’s correlation coefficient. For instance, correlation between body mass, muscle mass, fat free mass, fat mass, spirometry parameters and peak VO2, peak VO2 expressed as percentage predicted, first Ventilatory Threshold (VT) and maximal HR were explored. Pearson's correlation coefficient was calculated also for correlation between age, body composition and physical performance data. Regression analysis adjusted for age and height was performed to evaluate the association between variables which presented significant correlation as evaluated by Pearson's coefficient. Data were analyzed by STATA SE 16.1 (StataCorp LLC, College Station, TX, USA). The statistical significance was set at p ≤ 0.05.

Results

A total of 31 non-professional men's futsal athletes were evaluated during the mid-season. All athletes trained regularly 5 sessions per week for 1.5 h and a weekend game, mean years of training 7.32 ± 3.50. Mean age was 24.35 ± 4.69 years and mean body mass index (BMI) 23.69 ± 2.02 kg/m2. Mean fat mass in kilogram was 8.97 ± 3.06 kg and expressed as percentage of body mass: 12.24 ± 3.61. Mean FVC resulted 5.18 ± 0.57; and mean FEV1: 4.46 ± 0.61 l. Physical performance parameters were as follows: mean hand grip strength 43.45 ± 7.41 kg and mean peak VO2 expressed as percentage predicted: 106.45 ± 16.25 %. No significant differences resulted across age tertiles, except for muscle mass (MM) (p=0.03). Table 1 shows, in details measurements of body composition, spirometry and CPET in our study population and stratification in age tertiles. Pearson's correlation coefficient revealed a significant correlation between muscle mass and FEV1 and FVC; fat free mass and FEV1 and FVC. Significant correlations were also observed between body mass, muscle mass, fat free mass and peak VO2. Fat mass and fat mass percentage resulted inversely correlated with peak VO2% predicted; and 1st ventilatory threshold (VT). In addition, fat mass percentage inversely correlated with hand grip strength. Table 2 and Table 3 report the correlations between the above-mentioned parameters. Correlation analysis regarding age, years of training and body composition, spirometry and physical performance characteristics are reported in Supplementary Material Table 1. Finally, regression analysis showed that muscle mass and fat free mass significantly predicted respiratory parameters as FVC and FEV1 and fat mass and fat mass percentage predicted peak VO2 expressed as percentage of predicted VO2 max and handgrip strength. Regression analysis is summarized in Table 4.

Table 1.

Characteristics of futsal athletes stratified by age tertiles.

Characteristics	Overall Population (n= 31)	Tertile I (n=11)	Tertile II (n=10)	Tertile III (n=10)	p-value
Age, Mean SD	24.35 ± 4.69	19.54 ± 1.97	24.4 ± 0.97	29.6 ± 3.02	0.008
Gender Male, n (%)	31(100)	-	-	-	-
Years of training, Mean, SD	7.32 ± 3.50	4.81 ± 1.40	6.20 ± 1.22	11.2 ± 3.35	≤0.0001
Body Mass kg, Mean, SD	72.78 ± 8.13	71.01± 6.85	71.38 ± 4.74	76.13 ± 11.2	0.29
Height m, Mean, SD	1.75 ± 0.06	1.73 ± 0.05	1.77 ± 0.05	1.76 ± 0.08	0.33
BMI kg/m2, Mean, SD	23.69 ± 2.02	23.73 ± 2.10	22.81± 1.26	24.52 ± 2.36	0.17
FFM kg, Mean, SD	63.95 ± 7.01	61.73 ± 6.18	62.17 ± 2.90	68.17 ± 9.13	0.07
MM kg, Mean SD	60.26 ± 6.61	58.08 ± 4.59	58.08 ± 3.45	64.85 ± 8.72	0.03
MM %, Mean SD	83.05 ± 6.35	81.99 ± 4.40	81.78 ± 8.33	85.46 ± 5.83	0.35
FM kg, Mean SD	8.97 ± 3.06	8.40 ± 3.35	9.18 ± 2.47	9.39 ±3.46	0.75
FM%, Mean SD	12.24 ± 3.61	11.68 ± 3.97	12.92 ± 3.64	12.17± 3.42	0.74
FVC l, Mean SD	5.18 ± 0.57	4.95 ± 0.56	5.07 ± 0.57	5.55 ± 0.45	0.16
FVC % predicted, Mean SD	99.74 ± 11.32	97.36 ± 10.95	99.20 ± 10.68	102.90 ±12.71	0.54
FEV1 l, Mean SD	4.46 ± 0.61	4.33 ± 0.39	4.22 ± 0.61	4.84 ± 0.68	0.06
FEV1 % predicted, Mean SD	102.23 ± 11.91	101.27 ± 8.33	97.70 ± 12.02	107.80 ± 13.88	0.16
FEV1/FVC % predicted, Mean SD	102.30 ± 10.89	102.34± 10.59	99.4 ± 13.98	105.14 ± 7.49	0.51
Handgrip Strength Kg, Mean SD	43.45 ± 7.41	41.42 ± 4.97	43.79± 8.24	45.34 ± 8.87	0.49
HR rest bpm, Mean SD	60.97 ± 11.61	60.82 ± 15.57	62.80 ± 8.70	59.30 ± 9.88	0.81
VO2 rest ml/kg/min, Mean SD	4.95 ± 1.18	4.87 ± 1.11	5.13 ± 1.30	4.85 ± 1.21	0.84
VCO2 rest ml/min, Mean SD	0.28 ± 0.10	0.27 ± 0.98	0.32 ± 0.13	0.25 ± 0.07	0.32
peak VO2 ml/min, Mean SD	3372.17 ± 539.69	3433.51± 440.77	3282.33 ±706.73	3394.53 ± 491.34	0.81
peak VO2 ml/min/kg, Mean SD	46.53 ± 7.03	48.34 ± 4.04	46.13 ± 10.17	44.95 ± 6.03	0.55
peak VO2 % predicted, Mean SD	106.45 ± 16.25	109.91± 9.32	104.7 ± 23.00	104.4 ± 15.22	0.69
1st VT % peak VO2 predicted, Mean SD	75.11 ± 6.38	75.35 ± 7.95	75.53 ± 5.09	74.41 ± 6.02	0.92
peak HR bpm, Mean SD	164.65 ± 0.08	165.54 ± 10.75	165.90 ± 16.55	162.40 ± 9.26	0.79
peak O2 pulse ml/beat, Mean SD	21.50 ± 3.84	21.93 ± 3.91	20.87 ± 3.76	21.67 ± 4.15	0.82
peak RER	1.05 ± 0.08	1.04 ± 0.08	1.1 ± 0.07	1.01± 0.08	0.14
peak BR %, Mean SD	40.82 ± 7.38	42.83 ± 6.27	43.02 ± 8.38	36.4 ± 5.95	0.07
VE/VCO2 slope, Mean SD	29.08 ± 2.72	28.42 ± 3.2	28.45 ± 1.74	30.43 ± 2.73	0.17

BMI: body mass index; BR: breathing reserve; FFM: fat free mass; FM: fat mass; FEV1: forced expiratory volume in 1st second; FVC: forced vital capacity; HR: heart rate; MM: muscle mass; RER: respiratory exchange ratio; VCO2: carbon dioxide uptake; VE: ventilation; VO2: oxygen uptake; VT: ventilatory threshold.

Table 2.

Correlations between body composition and spirometry measurements.

	FEV1	FEV1 % predicted	FVC	FVC % predicted	FEV1/FVC % predicted
Body Mass	0.24	-0.02	0.28	-0.09	0.06
MM	0.47*	-0.01	0.53*	-0.14	0.10
MM%	0.33	0.01	0.36*	-0.06	0.06
FFM	0.46*	-0.02	0.51*	-0.15	0.12
FM	-0.04	-0.17	0.18	-0.03	-0.18
FM%	-0.14	-0.20	0.10	-0.01	-0.23

FEV1: forced expiratory volume in 1st second; FFM: fat free mass; FM: fat mass; FVC: forced vital capacity; MM: muscle mass. *Significant coefficient (p≤0.05).

Discussion

The present study showed that in a population of competitive futsal male athletes body composition parameters are significantly correlated with spirometry measurements and predict physical performance. De Mura et al.¹⁵ reported that body fat percentage in futsal players ranged from 10 to 13%. In our study we found a mean fat mass expressed as percentage of body mass of about 12%. Our results are in agreement with this previous report. Despite different studies have described anthropometric measures in futsal players of different competitive levels or playing positions, it should be highlighted that description of muscle mass was lacking.^1,2,16 A previous study, focused on description of body mass components in soccer players,¹⁷ reported a mean muscle mass of about 40 kg. However, in this study a wide range of age groups were included, and in football players under 20 years there was a lower absolute muscle mass compared to older age groups. In line with this study, our results also report a lower absolute muscle mass among younger futsal athletes. The mean muscle mass in our study resulted around 60 kg, and this may be explained by training programs and high intensity activities which characterize futsal match. Indeed, greater percentage of muscle mass contributes to higher energy production.¹⁸ As expected, muscle mass and respiratory parameters resulted significantly correlated. Physical activity has a direct influence on modification of body composition by reducing fat mass and increasing muscle mass, and ameliorates respiratory performance.^19-21 However, description of respiratory and musculoskeletal relationship in futsal athletes is not well established and our result is of interest considering also future studies which may explore respiratory adaptation in relationship to training programs and body composition modification in this population. Handgrip strength is a powerful indicator of muscle strength, and a significant relationship between muscle mass and handgrip strength has been described.²² Furthermore, loss of skeletal muscle mass is an important contributor to the age-related reduction in anaerobic power, even among master athletes.²³ In our population hand grip strength did not result significantly associated to muscle mass probably because of the limited number of participants and the young age of our participants. Of interest, higher fat mass was associated with lower handgrip strength. Most of the studies focus on muscle mass- handgrip strength relationship, and only a recent study focused on the relationship of muscle mass, fat mass and muscle strength among adolescents described a significant relationship of fat mass index with hand grip strength independently of muscle mass.²⁴ Our population was characterized by a mean peak VO2 of about 46 ml/kg/min and the first ventilatory threshold was reached at about 70% of the peak VO2. Our results are similar to another study, which described that peak VO2 of among futsal athletes ranged between 40 to 46 ml/kg/min.¹⁵ Other studies have shown higher peak VO2 levels, however these studies included professional or elite futsal players.^25-27 Our results indicate that reduced fat mass is characterized by increased hand grip strength and peak VO2 consumption. A previous study concluded that fat mass does not influence maximal VO2, and excess in adipose tissue does not necessarily imply reduction of VO2 consumption during exercise.²⁸ However, this study included pediatric population. In contrast, another study observed that increased fat mass percentage was associated with reduction of VO2 max in health young adults of age 18-25 years.²⁹ Of note, a recent study described that higher fat mass negatively affected aerobic power, and phase angel was positively associated to VO2 max.³⁰ Another study also reported that increased fat mass percentage reduces exercise capacity but VT was not effected by fat mass.³¹ In our study, fat mass negatively influenced VT, indicating that anaerobic threshold is influenced by body composition and the level of cardiorespiratory fitness in futsal players depends also on adipose tissue. Furthermore, monitoring of fat mass variations in futsal athletes may indicate modifications in their physical performance status. In addition, training program and nutritional lifestyle should be also targeted to fat mass distribution. CPET is the gold standard for the evaluation of physical capacity and peak VO2 is a well- established parameter of physical performance status. In the context of sports medicine, identification of body composition parameters associated with physical performance is of great importance. Assessment of body composition characteristics as fat mass and muscle mass which predict physical capacity parameters in competitive futsal athletes is useful to establish what modifications may be adapted to ameliorate physical capacity. In addition, fat mass estimation through bioelectrical impedance analysis (BIA) may represent a support for screening of physical capacity and monitoring of training programs. Over the past years, different methods have been applied for the measurements of body composition. Despite dual-energy x-ray absorptiometry is still the gold standard of body composition evaluation, bioelectrical impedance analysis (BIA) is a safe, easy to use method which allows valid, reliable and replicable estimation of body composition.^32,33 It should be mentioned that estimation of fat mass by BIA is based on predictive equations developed for not physical active or general athletic population.³³ Of interest a recent study reported that anthropometry based generalized equations overestimated fat mass percentage, while BIA based generalized equations underestimated this parameter in futsal athletes.³⁴ Furthermore, this study demonstrated that a futsal-specific equation allows a more accurate and precise fat mass percentage estimation by using BIA or anthropometric measures interchangeably. Limitations of study are that it is a single center observational study including a limited number of participants. Other characteristics of body composition may be better explored including a larger number of participants, and other methods as magnetic resonance and dual-energy x-ray absorptiometry may give a more accurate estimation of muscle mass. Furthermore, the effects of different types of training among futsal athletes may influence the results. Caution is necessary when interpreting body composition data estimated from equations which derive from general athletic population and not specific to sports discipline. We could not include female participants and our results cannot be generalized also to female population. In conclusion, in futsal competitive athletes body composition influence the cardio-respiratory fitness. Increased muscle mass is associated with higher spirometry parameters and fat mass is inversely associated to lower cardiorespiratory fitness. Future studies should explore if targeting fat mass would ameliorate the physical performance in this population.

Table 3.

Correlations between body composition and physical performance measurements.

	Hand grip strength	peak VO2 ml/min	peak VO2 % predicted	1st VT% predicted	Peak HR
Body Mass	0.03	0.4*	-0.28	-0.31	-0.18
MM	0.05	0.36*	-0.15	-0.29	-0.29
MM %	0.01	-0.10	0.16	0.01	-0.17
FFM	0.07	0.39 *	-0.18	-0.23	-0.33
FM	-0.28	-0.16	-0.51*	-0.52*	-0.17
FM%	-0.38*	-0.37*	-0.55*	-0.47*	-0.13

FFM: fat free mass; HR: heart rate; MM: muscle mass; peak VO2: peak oxygen uptake; VT: ventilatory threshold. *Significant coefficient (p≤0.05).

Table 4.

Regression analysis of FVC, FEV1, peak VO2% predicted and hand grip strength.

Variable	R2	Coefficient Beta	p-value
		FVC
MM	0.32	0.04	0.02
FFM	0.31	0.04	0.03
		FEV1
MM	0.26	0.04	0.03
FFM	0.27	0.04 peak VO2% predicted	0.03
FM	0.32	-2.10	0.001
FM%	0.30	-2.47	0.002
		1st VT
FM	0.27	-1.08	0.003
FM%	0.22	-0.82	0.009
		Hand Grip Strength
FM%	0.25	-0.76	0.032

1st VT: first ventilatory threshold; FFM: fat free mass; MM: muscle mass; FEV1: forced expiratory volume in 1st second; FVC: forced vital capacity; peak VO2: peak oxygen uptake predicted

List of acronyms

1st VT

first ventilatory threshold

BMI

body mass index

BR

breathing reserve

CPET

cardio-pulmonary exercise testing

FEV1

forced expiratory volume in 1st second

FFM

fat free mass

FIFA

International Association Football Federation

FM

fat mass

FVC

forced vital capacity

HR

heart rate

MM

muscle mass

Peak VO2

peak oxygen uptake

Peak VO2 predicted

peak oxygen uptake predicted

RER

respiratory exchange ratio

VCO2

carbon dioxide uptake

VE.

ventilation

VO2

oxygen uptake

VT

ventilatory threshold

Funding Statement

Funding: None.