The validity and reliability of the six-minute pegboard and ring test for assessing upper extremity exercise capacity in individuals with overweight and obesity: a cross-sectional study

Abstract

Background

High body mass is associated with functional limitations affecting both the lower and upper extremities. While the 6-minute pegboard and ring test (6PBRT) is a validated measure of upper extremity exercise capacity in various clinical populations, its clinimetric properties across the broader spectrum of individuals with overweight and obesity remain to be fully established. The aim of this study was to investigate the reliability and validity of the 6PBRT in individuals who are overweight and obesity.

Methods

A sample of 51 participants (BMI ≥ 25 kg/m², aged 18–65 years) was included. Exercise capacity of the upper extremities, functional capacity, muscle function and upper extremity functional status were evaluated using the 6PBRT, 6-minute walk test (6MWT), handgrip strength (HGS) and the 30-second push-up test and Upper Extremity Functional Index (UEFI), respectively. Reliability was analysed using intraclass correlation coefficients (ICC) and validity was examined by correlation analyses.

Results

The 6PBRT showed good test–retest reliability (ICC = 0.884; 95% CI: 0.797–0.934; p < 0.001), and a substantial enhancement was evident when comparing the initial and subsequent tests (396.59 ± 60.77 vs. 432.59 ± 79.95; p < 0.001). Moderate correlations were observed between 6PBRT and 6MWT (r = 0.420, p = 0.002; r = 0.486, p < 0.001). In addition, weak but statistically significant correlations were found between the 6PBRT and dominant HGS (r = 0.292, p = 0.037; r = 0.291, p = 0.039), non-dominant HGS (r = 0.345, p = 0.013; r = 0.330, p = 0.018), 30-second push-up test (r = 0.302, p = 0.031; r = 0.332, r = 0.017) and UEFI scores (r = 0.366, p = 0.008; r = 0.331, p = 0.018).

Conclusions

The 6PBRT is a reliable and valid tool for evaluating exercise capacity in the upper extremities of individuals with overweight and obesity. It may also be useful for assessing functional performance in clinical and rehabilitation settings.

Trial registration

ClinicalTrials.gov (NCT06742112), registered 16 December 2024.

Background

Obesity is a preventable disease with a multifactorial aetiology that includes genetic, environmental, socio-economic, behavioural and psychological influences. Body mass index (BMI) is a method used to identify individuals who are overweight or obesity [1], and increased BMI is identified as a factor associated with functional task limitations [2]. Previous studies have reported that individuals with overweight and obesity have decreased flexibility, which affects their functional capacity and physical performance [3, 4]. Evidence indicates a significant inverse correlation between elevated BMI and upper body physical fitness [5]. There may also be differences in posture. For individuals of normal weight, the arms hang down by the sides of the body in a resting position, with the palms facing the thighs or close to them. In obese individuals, however, the palms face backwards [6]. This condition may restrict the functional capacity of the upper extremities in individuals with overweight and obesity. The upper extremities are crucial for positioning the hands in order to push, carry, manipulate, lift, pull and grip objects, and are essential for performing activities of daily living. Problems with the upper extremity can lead to functional loss and difficulty performing activities of daily living [7].

Tests such as 6-minute walk test (6MWT) and hand grip strength (HGS) are commonly used to assess general functional performance as they are simple, low-cost, and widely validated in different populations [8–10]. However, 6MWT commonly focuses on lower extremity performance, while HGS reflects isolated muscle strength and cannot adequately capture the unsupported upper extremity endurance required during continuous, repetitive daily activities. This increases the need for a functional test such as the 6PBRT [8–11].

The gold standard method for assessing upper limb exercise capacity is arm ergometer testing [12, 13]. However, this test requires a laboratory environment and expensive equipment, as well as taking relatively more time than functional tests. Nonetheless, functional arm tests more accurately reflect daily life activities. The 6-minute pegboard and ring test (6PBRT) is recognized as a reliable and valid assessment of unsupported upper extremity endurance across various clinical groups. Previous research has validated its efficacy in populations with asthma, breast cancer, pulmonary arterial hypertension, multiple sclerosis, and chronic obstructive pulmonary disease [11, 13–16]. While 6PBRT has been established as a psychometrically sound measure across various chronic conditions, its application for weight-related functional limitations is a developing area of research. Recently, Özsoy et al. validated the 6PBRT specifically within a population with obesity [17]. However, there remains a need to confirm these clinimetric properties across the broader spectrum of individuals with both overweight and obesity. Furthermore, exploring the relationship between the 6PBRT and diverse measures such as the 30-second push-up test and self-reported functional status is essential to fully understand its clinical utility in this population. Our study aimed to investigate the validity and reliability of the 6PBRT for assessing upper extremity exercise capacity in individuals who are overweight and obesity, while further examining its relationship with diverse functional and muscular measures.

Methods

Study design and participants

This cross-sectional study was carried out in the Department of Physical Therapy and Rehabilitation at Kırşehir Ahi Evran University throughout the period from December 2024 to June 2025. The study was approved by the Kırşehir Ahi Evran University Health Sciences Scientific Research Ethics Committee (protocol number 2024-20/173) and it conforms to the provisions of the Declaration of Helsinki. It is also registered at ClinicalTrials.gov (NCT06742112). The study included individuals aged 18–65 with a BMI of 25 or over who were willing to participate. The study excluded individuals with a known chronic or systemic disease, conditions that could affect physical function, a history of bariatric surgery, or who were pregnant or had a contraindication to exercise testing. All participants signed an informed consent form. The demographic information of the participants was recorded. The sample size for this study was determined based on the findings of Kahraman et al., who established the validity of the 6PBRT in individuals with pulmonary hypertension. Utilizing the correlation between 6PBRT scores and age (r =-628, p < 0.001) reported in that study, we calculated that a minimum of 22 participants was required to achieve a statistical power of 90% [14]. A post-hoc power analysis conducted using G*Power (version 3.1) indicated that with our final sample of 51 participants and the observed correlation between the 6PBRT and age (r=-0.377, p = 0.006), the study achieved a statistical power of 81.3% (α = 0.05).

Upper extremity exercise capacity

The upper extremity exercise capacity of participants was assessed using the 6-minute pegboard and ring test (6PBRT). The assessment was performed with the participant seated in a standard chair without armrests to ensure unrestricted movement. The pegboard apparatus consisted of two horizontal bars, each equipped with two pegs. The board was adjusted so that the lower bar was positioned exactly at the level of the participant’s shoulders, while the upper bar was positioned 20 cm above shoulder height. Participants were instructed to move rings from the lower pegs to the upper pegs and then back again as quickly as possible. This process was performed using both hands simultaneously for a duration of six minutes. Standardized verbal encouragement was provided every minute, consistent with established protocols for functional exercise tests. The total number of rings moved during the six-minute period was recorded (Fig. 1) [15]. To evaluate test-retest reliability, the 6PBRT was performed twice. The test was repeated after a 30-minute rest period to allow for adequate physiological recovery and to minimize the impact of fatigue.

Fig. 1.

Visual representation of 6PBRT and the participant

Functional capacity

The functional capacity of the participants was evaluated using the 6MWT, conducted in accordance with the American Thoracic Society (ATS) guidelines. The test was performed on a 30-meter-long, flat corridor and turnaround points were clearly identified. Participants were instructed to walk back and forth along the corridor at their own pace, attempting to cover as much distance as possible within six minutes. They were permitted to stop and rest if necessary but were encouraged to resume walking as soon as they felt able. Standardized verbal encouragement was provided at one-minute intervals using the established ATS phrasing. The total 6MWT distance was recorded in meters [18].

Muscle function

Hand grip strength was evaluated using a grip dynamometer (Jamar, Fabrication Enterprised Inc, Irvington, USA) while individuals maintained a standardized seated position with their knees and elbows at 90° flexion. Participants held the dynamometer adjacent to the trunk and were instructed to exert their maximal gripping force with the wrist in a neutral position. The measurement procedure involved three separate trials for both the dominant and non-dominant hands, with a 10-second rest interval between each effort. The highest value recorded in kilograms of force (kgF) was selected for the final analysis [19]. The 30-second push-up test was used to evaluate the strength and endurance of the muscles in the arms and shoulder girdle. During the test, it was recorded how many times the person performed the movement of bringing the body closer to the floor and returning to its original position for 30 s, with the knees not touching the ground, elbows straight, and arms in a supported position, upon command [20].

Upper extremity functional status

The Upper Extremity Functional Index (UEFI) was used to assess functional status. This index is used to evaluate functional status in individuals with upper extremity problems, and comprises 20 questions designed to evaluate daily living activities, such as housework, carrying bags, cleaning and getting dressed. The total score is obtained by summing the points obtained from the questions, and a higher score indicates a better functional status [21].

Statistical analysis

The statistical analysis was performed in SPSS Statistics, version 29.0. The Kolmogorov-Smirnov test was used to evaluate whether the data were normally distributed. Descriptive data were expressed as mean and standard deviation (SD), as well as number and frequency. The statistical significance level was set at p < 0.05. Reliability was assessed using the intraclass correlation coefficient (ICC). An ICC of < 0.50 was interpreted as poor, 0.50–0.75 as moderate, 0.75–0.90 as good, and > 0.90 as excellent reliability [22]. The standard error of measurement (SEM) and the minimum detectable change (MDC) were calculated using the following formula as SEM = SD√(1-ICC), MDC = SEM×1.96×√2 [23]. Depending on the normality of the data distribution, either Pearson or Spearman correlation coefficients were calculated to evaluate the relationships between both the first and second 6PBRT trials and the 6MWT distance, HGS, 30-second push-up test, and UEFI scores. The correlation coefficients were defined as negligible (0.0–0.19), weak (0.20–0.39), moderate (0.40–0.69), strong (0.70–0.89) or very strong (0.90–1.0) [22].

Results

The eligibility of 62 participants was evaluated. A total of 11 individuals were excluded from the study: 2 had chronic lung disease, 1 had diabetes mellitus, 1 had a musculoskeletal problem affecting physical function, and 7 individuals refused to participate. The study included a total of 51 participants (68.9% female) (Fig. 2). Of these, 49% were overweight and 51% were obese. Table 1 presents the demographic and clinical characteristics of the participants.

Fig. 2.

Flow diagram for participants

Table 1.

Participant’s characteristics

	Mean ± SD
Age (years)	31.51 ± 11.01
Female/Male (n/%)	35 (68.9%)/16 (31.4%)
Height (cm)	167.39 ± 9.21
Weight (kg)	85.68 ± 13.63
Body Mass Index (kg/m2)	30.63 ± 4.70
Overweight (25.0–29.9 kg/m2)	25 (49%)
Obese (≥ 30.0 kg/m2)	26 (51%)
6PBRT (n) (First test)	396.59 ± 60.77
6PBRT (n) (Second test)	432.59 ± 79.95
6MWT (m)	569.56 ± 69.28
Dominant HGS (kgF)	31.02 ± 10.66
Non-dominant HGS (kgF)	28.96 ± 10.64
30-second push-up test (n)	14.08 ± 8.51
UEFI	69.65 ± 11.28

n frequency, % percentage, cm centimeter, kg kilogram, 6PBRT 6 min pegboard and ring test, 6MWT 6 min walk test, HGS Hand grip strength, kgF kilogram-force, UEFI Upper Extremity Functional Index

A test-retest reliability analysis of the 6PBRT revealed a strong correlation between the first and second tests, with an ICC of 0.884 (95% Cl:0.797–0.934; p < 0.001), and the SEM was 20.66 and the MDC 57.25, suggesting good reliability. The total number of rings moved in the 6PBRT increased significantly from the first test (396.59 ± 60.77) to the second test (432.59 ± 79.95) (< 0.001), and these values were also strongly correlated (< 0.001) (Table 2).

Table 2.

Measurement reliability of the 6PBRT in individuals with overweight and obesity

6PBRT	First Test (n)	Second Test (n)	p	ICC	95%CI	p	SEM	MDC
	396.59 ± 60.77	432.59 ± 79.95	< 0.001	0.884	0.797–0.934	< 0.001	20.66	57.25

6PBRT 6 min pegboard and ring test, ICC Intraclass correlation coefficient, SEM Standard error of measurement, MDC Minimal detectable change

Subgroup analysis revealed that 6PBRT scores did not differ significantly between participants with overweight and those with obesity in the first 6PBRT trial (394.16 ± 59.66 vs. 398.92 ± 62.90) or the second 6PBRT trial (435.60 ± 65.61 vs. 429.69 ± 92.91) (p > 0.05).

Correlation analyses showed that 6PBRT results in the first and second tests were significantly linked to all functional and muscle performance measurements. There was a moderate positive correlation between both the first and second 6PBRT and the 6MWT distance (r = 0.420, p = 0.002; r = 0.486, p < 0.001, respectively. A weak positive correlation was observed between both the first and second 6PBRT dominant HGS (r = 0.292, p = 0.037; r = 0.291, p = 0.039), non-dominant HGS (r = 0.345, p = 0.013; r = 0.330, p = 0.018), 30-second push-up repetition score (r = 0.302, p = 0.031; r = 0.332, p = 0.017) and UEFI score (r = 0.366, r = 0.008; p = 0.331, r = 0.018) (Table 3).

Table 3.

Correlations between 6PBRT and functional parameters in individuals with overweight and obesity

	6PBRT (First)		6PBRT (Second)
	r	p	r	p
6MWT (m)	0.420	0.002*	0.486	< 0.001*
Dominant HGS (kgF)	0.292	0.037*	0.291	0.039*
Non-dominant HGS (kgF)	0.345	0.013*	0.330	0.018*
30-second push-up test (n)	0.302	0.031*	0.332	0.017*
UEFI	0.366	0.008*	0.331	0.018*

6PBRT 6 min pegboard and ring test, 6MWT 6 min walk test, HGS Hand grip strength, kgF kilogram-force, UEFI Upper Extremity Functional Index

Discussion

As a result of our study, the validity and reliability of 6PBRT in evaluating upper extremity exercise capacity in individiuals who are overweight and obese were demonstrated, thus confirming the effectiveness of the test in this specific context. Moderate positive correlations were observed between the 6PBRT and the 6MWT, providing evidence that upper limb endurance is linked to overall functional exercise capacity. Though it reflects a distinct construct, weak but significant associations with HGS, push-up performance and the UEFI demonstrate that the 6PBRT also indicates aspects of muscular strength and perceived function in individuals with overweight and obese.

There are studies in the literature reporting that the upper extremity functions of individuals with overweight and obesity are affected. Zadon et al. reported that an increase in BMI causes fatigue during daily activities performed and an additional external load occurs during activities such as lifting and holding an object [24]. A further study indicates that individuals with obesity have considerable restrictions on their upper body’s range of motion when performing basic occupational tasks [25]. The 6PBRT reflects the capacity of the upper extremities in relation to activities of daily living, and its validity and reliability have been demonstrated in many populations including asthma, pulmonary hypertension and breast cancer. The findings of our study are in line with those of earlier research, as demonstrated by the reliability of 6PBRT in individuals who are overweight and obesity [11, 13, 14]. Specifically, our findings align with the recent study of Özsoy et al., who also confirmed that the 6PBRT is a reliable and valid tool for assessing upper extremity exercise capacity in individuals with obesity [17]. Similar to their results, our data showed high test–retest reliability (ICC = 0.884). However, our study extends this evidence by including individuals categorized as overweight (BMI ≥ 25 kg/m²), suggesting that the 6PBRT remains a robust measure across the broader spectrum of excess body weight. A further distinction is that our study specifically excluded individuals with known chronic or systemic diseases to isolate the effects of overweight and obesity on functional capacity.

The results showed a clear improvement in performance from the first 6PBRT (396.59 ± 60.77) to the second (432.59 ± 79.95), demonstrating a learning effect. The learning effect mentioned is in line with what has been suggested in previous literature, which says that this test should be given twice [11, 26]. This enhancement in performance is probably attributable to an accumulation of experience with the testing procedure, such as the identification of a more efficacious method of gripping the rings. Consequently, we recommend applying 6PBRT twice to evaluate the upper extremity exercise capacity of individuals with overweight and obesity, taking into account the learning effect, and interpreting the best result.

The 6MWT is a simple, low-cost, submaximal test that involves multiple body systems, including the pulmonary, cardiovascular and muscular systems. It is widely used to evaluate functional capacity in people of different ages and with different health conditions [10]. Consistent research has shown that BMI negatively impacts 6MWT performance, with a higher BMI being associated with shorter walking distances- presumably due to increased mechanical and metabolic demands [27]. Our finding of a moderate positive correlation between the first and second 6PBRT tests and the 6MWT distance suggests a notable link between upper extremity endurance and lower extremity functional capacity in individuals with overweight and obesity. This result highlights the fact that performance on the 6PBRT may reflect not only the functional capacity of the upper extremities, but also general cardiopulmonary and musculoskeletal endurance. Our study’s findings align with those of other research, which has also identified a correlation between upper body muscle performance and 6MWT outcomes across diverse populations such as patients with heart failure with reduced ejection fraction and older individuals [28, 29]. These results support the idea that individuals with better upper-extremity function are more likely to have greater walking capacity due to their preserved aerobic capacity. The shared physiological and biomechanical requirements of upper- and lower-extremity functions suggest a general interaction in functional endurance in individuals who are overweight and obesity. Furthermore, this relationship, our study provides novel evidence that the 6PBRT can serve as a valuable indicator of functional status in this population, particularly when lower-limb weight-bearing activities are restricted.

Our study found correlations between the 6PBRT score and HGS. Consistent with the findings of our study, Özsoy et al. investigated the relationship between 6PBRT and HGS in COPD patients [30], while Ozcan-Kahraman et al. examined this relationship in individuals with pulmonary arterial hypertension [14]. Information about upper extremity muscle strength is commonly obtained by assessing HGS. This finding aligns with prior studies highlighting that HGS assessment, while informative, does not serve as an independent gauge of upper body strength or performance, especially in contexts requiring prolonged effort or dynamic movement [31, 32]. In our study, the weak correlations with HGS highlight that the contribution of static, isometric upper limb strength to performance in an endurance-based functional test such as the 6PBRT is only partial. On the other hand, the 30-second push-up test reflects dynamic upper-body endurance and showed a weak correlation with the 6PBRT, suggesting limited overlap in muscle endurance demands between the two tests. The correlation observed between the unsupported upper extremity exercise test and the 30-second push-up test in individuals with chronic neck pain strengthens the hypothesis that dynamic, unsupported upper extremity activities have shared endurance requirements [33]. Given the similar magnitude of the correlation coefficients for HGS and the 30-second push-up test, both measures appear to demonstrate a limited and comparable association with functional upper extremity capacity in individuals who are overweight and obesity.

The UEFI is a patient-reported outcome measure that has been used to evaluate difficulties with activities involving the upper extremities [34]. The findings of our study demonstrated that, although not strong, there were noteworthy connections between 6PBRT performance and self-reported upper extremity function on the UEFI. This result is expected when an endurance-based performance test (6PBRT) is compared with a patient-reported measure (UEFI) that encompasses a broader range of activity limitations and symptoms. Self-reported function and performance are generally consistent. Nevertheless, while performance is related to age and physiological factors, self-reported functional impairment is also associated with psychosocial and health factors [35]. Likewise, it was demonstrated that there was no significant correlation between performance-based balance measures and self-reported function in athletes experiencing shoulder pain. This result has been interpreted to mean that self-reports are subjective and reflect individuals’ perceptions of function, whereas performance tests objectively assess individuals’ physical capacity and can detect changes before they become apparent in self-report measures [36].

This study has some limitations. First, the relatively small, single-center sample size restricts the generalisability of the results. Second, it is not possible to evaluate causal relationships or responsiveness of the 6PBRT to interventions because of the cross-sectional design. Third, the predominance of female participants (~ 69%) may affect the generalizability of these findings to males with overweight or obesity. Finally, the absence of a healthy or normal-weight control group prevented comparisons with normative data, making it difficult to determine whether the observed 6PBRT scores represent a functional impairment relative to healthy or lean individuals.

Conclusions

This study showed that the 6PBRT can be used to reliably and validly assess the exercise capacity of the upper extremities in individuals with overweight and obesity. The findings indicate a link between 6PBRT and the six-minute walk test, muscle functions, and UEFI. This suggests that the 6PBRT reflects muscle performance and functional abilities associated with daily living. Taken together, these results suggest that the 6PBRT could be a practical, low-cost method of evaluating upper extremity function in individuals at risk of functional limitations due to excess body weight. To confirm its responsiveness and clinical usefulness in a wider range of rehabilitation contexts, further longitudinal and intervention-based studies with larger and more diverse groups are required.

Abbreviations

6MWT

6-minute walk test

6PBRT

6-minute pegboard and ring test

BMI

Body mass index

HGS

Handgrip strength

ICC

Intraclass correlation coefficients

kgF

Kilograms of force

MDC

Minimum detectable change

SD

Standard deviation

SEM

Standard error of measurement

UEFI

Upper Extremity Functional Index

Authors’ contributions

Conceptualisation: MF; Data curation: MF, EB, HIK, OG; Formal analysis: MF; Supervision: MF; Writing-original draft: MF, EB, HIK, OG; Writing-review and editing: MF.

Funding

No financial support is available for the study.

Data availability

The datasets used and/or analysed during the current study are available from the corresponding author on reasonable request.

Declarations

Ethics approval and consent to participate

This study was approved by Kırşehir Ahi Evran University Health Sciences Scientific Research Ethics Committee (2024-20/173). All participants signed an informed consent form.

Consent for publication

Written informed consent was obtained from the participant for the publication of the image included in this manuscript.

Competing interests

The authors declare no competing interests.