Contralateral Muscle Imbalances and Physiological Profile of Recreational Aerial Athletes

Preparation For Flight: The Physical Profile of Pre-Professional and Professional Circus Artists in the United States

Background

Established norms for fitness and performance measures are lacking in circus arts. These would assist healthcare professionals and coaches to screen for readiness to participate in training or performance, determine post-injury return to performance, and develop targeted conditioning programs.

Purpose

The purpose of this research was to establish norms for trunk and extremity physical exam and performance measures in circus artists by professional status, assigned sex at birth (ASAB), and age.

Study Design

Descriptive laboratory study.

Methods

Circus artists (n=201; ages 13-69y; 172 females ASAB, 29 males ASAB) from 10 cities across the United States underwent a baseline physical examination including shoulder, hip and trunk measures of passive (PROM) and active (AROM) range of motion, measures of flexibility (shoulder and hip), strength (manual muscle tests, grip strength), cardiovascular fitness (3 minute-step test), balance (single limb and handstand), and performance, (pull-ups, and the closed kinetic chain upper extremity stability test [CKCUEST]). ANOVAs were used to determine between group differences by age and T-tests to discern differences by ASAB or professional status.

Results

Differences existed by professional status for shoulder external rotation PROM, hip PROM, hip flexibility, shoulder and abdominal strength, and cardiovascular fitness. Sex differences were seen in active scapular upward rotation, hip and shoulder PROM and flexibility, hip and grip strength, and for functional performance measures (pull-ups, CKCUEST). Differences by age were limited to active scapular upward rotation, shoulder PROM, flexibility and strength, cardiovascular fitness, and balance. Overall, professionals outperformed pre-professionals for lower abdominal strength, pull-ups, handstand balance, cardiovascular fitness, hamstring, and straddle flexibility. Generally, males ASAB demonstrated greater shoulder flexibility and upper body functional strength while females ASAB had greater hip and lumbar flexibility and hip strength. No measures showed consistent declines with increasing age, though some showed differences between adolescents and adults.

Conclusion

These normative values for physical characteristics and functional performance in pre-professional and professional circus artists may be used to guide screening for readiness to participate in advanced training or performance, return to performance after injury, and the development of targeted strength and conditioning programs.

Level of Evidence

3.

Strength Training Perceptions Amongst Vocational Circus and Dance Students

Introduction: The aim of this study was to analyze perceptions of strength training in vocational circus and dance students. It was hypothesized that due to the higher relative strength demands and associated risks of working at height in some aerial and acrobatic disciplines that circus students would be more open to strength training than dancers. Methods: Eighty students completed the Training Information Survey (TIS) (Mean age = 20.74 ± 2.71); 39 circus students and 41 dance students. 97% of circus students and 69% of dance participants reported that strength training was a required part of their training with students participating in strength training 4.24 ± 0.98 and 3.05 ± 1.42 day per week respectively. Results: Perceptions of strength training amongst vocational circus and dance students appear to be favorable, with both sets of students strongly agreeing with the statements "Strength training is essential to my overall development as a dancer/circus artist" (5.00 (IQR 1.00) and 5.00 (IQR 1.00) respectively). Following Bonferonni correction only one statement returned statistically significant results with dance students agreeing more strongly with the statement "Strength training increases muscle size," U = 473.00, P = .001. Students also agreed that strength training helped them to feel better mentally and physically, that strength training is beneficial for both men and women and that it should not be designated as specific to either sex. Conclusion: Results support earlier studies that suggest a cultural shift in perceptions of strength training and ideal esthetic in dance, particularly amongst students and that they are keen to incorporate strength training into their practice. Educational establishments should note students' interest in participating in strength training, reviewing how to embed effective strength training education, more coaching and time allowance for these activities within their timetable. Further research with a greater sample size is recommended to further substantiate these indications of a shift in perceptions.

The relationship between handgrip strength and performance scores in North American Collegiate Division I women’s artistic gymnasts

Maximal isometric handgrip strength (HGS) is used as an indicator of overall muscular strength and has also been found to be predictive of certain athletic events sporting prowess. Women’s artistic gymnastics requires athletes have high levels of relative muscular strength and power to be successful. This study examined the relationship between HGS and gymnastics performance scores for the 4 events of vault, uneven bars, beam, and floor in female collegiate artistic gymnasts. Twenty-five (n=25) female National Collegiate Athletic Association (NCAA) Division I North American collegiate women’s artistic gymnasts (age: 20.1±1.3 yrs; height: 158.9±5.6 cm; mass: 58.2±5.3 kg) were assessed for a one-time measurement of absolute HGS in kg and relative HGS (HGS/height in m2), as well as their average vault, uneven bars, beam, and floor performance scores across a competitive season. Pearson correlation coefficients (r) were determined between HGS and all performance scores. No significant (p > 0.05) correlations were found between absolute HGS (30.8±4.4 kg) or relative HGS (12.0±1.6 kg/m2) and any 4 gymnastics event’s performance scores (r range: -0.07 – 0.50 or r range: -0.06 – 0.31, respectively). In this female collegiate gymnastics’ population, 56% had an absolute HGS and 80% had a relative HGS, respectively, above the 50th percentile of all similarly aged adult females in the United States. In the current population of female collegiate gymnasts, absolute and relative HGS were not related to any gymnastics events performance scores and adds to the existing literature, supporting no relationships between HGS and sports performances where sports movements require a high degree of technical precision and accuracy. Findings from this investigation can be used by athletes, coaches, and practitioners in the collegiate women’s gymnastics realm to assess if athletes have attained sufficient absolute HGS, and especially relative HGS values, to be successful.

Prevalence of muscle imbalance and its potential influence on injury among female acrobatic dancers

Objective

The purpose of this study was to determine the prevalence of muscle imbalance among young adolescent acrobats (n=15) and if there was a potential link to injury.

Methods

Isokinetic strength of the lower extremity, isometric strength of the trunk, and flexibility of both the trunk and lower extremity were assessed. Pearson correlation (r) and χ² correlation tests were performed on all explanatory variables.

Results

Significant correlations were found between isokinetic peak torque of the quadriceps and hamstrings (p=0.000) and the plantar flexors and dorsiflexors (p=0.000) on both sides, along with plantar flexor dominance (p=0.000). Non-significant findings were seen when identifying dominance between the quadriceps and hamstrings (p=0.933) as well as when correlating peak torque and flexibility of the lower extremity (right hamstrings: p=0.668, left hamstrings: p=0.338, right quadriceps: p=0.171, left quadriceps: p=0.707, right plantar flexors: p=0.282, left plantar flexors: p=0.382, right dorsiflexors: p=0.297 and left dorsiflexors: p=0.393).

Conclusion

Acrobats demonstrated noticeably high ranges of flexibility, and the most common injury site was found to be the ankle. However, these mentioned injuries were not all due to acrobatic participation. The limited sample size warrants extensive research with a larger sample size to further verify or dispute the results found in this study. Muscle imbalances found within this population could increase the risk of injury.