Sex differences in power decrement identified across the lifespan

Muscular power has been shown to be a significant predictor of physical function in older adults, but assessments of power have traditionally been performed in movements not specific to activities of daily living (ADLs). Recent research examined power in the context of ADL-specific movements, but it is unclear how ADL-specific lower-body power differs over lifespan in males and females. This investigation sought to describe ADL-specific power decline across the lifespan and analyze differences between the sexes. Adults (n = 557) aged 18-89 volunteered and were divided into age cohorts (18-30, 50-59, 60-69, 70-79, and 80-89 years). Participants performed a sit-to-stand (STS) task with as much velocity as possible while connected to a linear position transducer (LPT). The LPT calculated average and peak power. The average result of 5 individual STS trials was analyzed for each of the power variables. The first significant decrement in average STS power (p < .01) was observed at an earlier age cohort in males than females (60-69 in males vs. 70-79 in females). The per decade magnitude of power decrement after age 60 was larger in males than females in both absolute magnitude and percent decrease (11.74 vs. 10.09% decrease per decade). As power and physical function are correlated, this may have implications for the rate and age of functional decline in males. Additionally, understanding the differences in ADL-specific power decline between males and females gives clinicians and health professionals valuable information for developing preventative fitness paradigms specific to members of a given sex.

Effect of a Supervised Stretching Program on Neck, Shoulder, and Trunk Range of Motion in Older Women

Upper body and neck range of motion (ROM) are important for safe walking and driving. The purpose of this study was to determine whether stretching would improve neck, trunk, and shoulder ROM. Forty-eight community-dwelling women (75 ± 3 years of age) were randomly allocated to intervention (upper body stretching, n = 15) and control conditions (lower body power training, n = 33). All participants exercised in supervised 45-minute sessions twice weekly for 12 weeks. Testing of upper body ROM included a cervical ROM, device-based measurement and field tests of the neck, trunk, and shoulder ranges. Shoulder ROM was the only movement that improved in the intervention group beyond levels seen in control participants (33% increase, p < 0.01). Neck and trunk ROM did not change in response to a specific stretching program. Older adults with ROM limitations may need to explore other exercise options or focus on compensatory strategies for safe community mobility.

Secular trends in health-related physical fitness among 11–14-year-old Croatian children and adolescents from 1999 to 2014

The main purpose of the study was to analyze secular trends of health-related physical fitness in 7–14-year-old Croatian children and adolescents from 1999 and 2014. In this observational cross-sectional study, we recruited 5077 children and adolescents between ages 11 and 14 (50.8% girls) from five primary schools located in the capital city of Zagreb. Physical fitness performance was tested from 1999 until 2014. Physical fitness performance included: (1) body-mass index (measure of body size), (2) standing broad jump (measure of lower-body power), (3) polygon backwards (measure of general coordination and agility), (4) sit-ups in 60 s (measure of upper-body strength), (5) sit-and-reach test (measure of flexibility) and (6) 6-min run test (measure of cardiorespiratory fitness). Boys performed better in all physical fitness tests, except for sit-and-reach test (p < 0.001). In boys, between 1999 and 2014, body size, upper-body strength and coordination/agility increased, while flexibility, lower-body power and cardiorespiratory fitness decreased. During the same period, girls experienced an increase in body size, lower-body power, upper-body strength, coordination/agility and flexibility, while cardiorespiratory fitness decreased. This study shows that cardiorespiratory fitness, flexibility and coordination/agility decrease, while upper-body strength increases in both sexes. These findings should serve as an avenue for national monitoring system to screen and track biological development in children and adolescents.

The anthropometric and physical qualities of women’s rugby league Super League and international players; identifying differences in playing position and standard

Participation in women's rugby league has been growing since the foundation of the English women's rugby league Super League in 2017. However, the evidence base to inform women's rugby league remains sparse. This study provides the largest quantification of anthropometric and physical qualities of women's rugby league players to date, identifying differences between positions (forwards & backs) and playing standard (Women's Super League [WSL] vs. International). The height, weight, body composition, lower body strength, jump height, speed and aerobic capacity of 207 players were quantified during the pre-season period. Linear mixed models and effects sizes were used to determine differences between positions and standards. Forwards were significantly (p < 0.05) heavier (forwards: 82.5 ± 14.8kg; backs: 67.7 ± 9.2kg) and have a greater body fat % (forwards: 37.7 ± 6.9%; backs: 30.4 ± 6.3%) than backs. Backs had significantly greater lower body power measured via jump height (forwards: 23.5 ± 4.4cm; backs: 27.6 ± 4.9cm), speed over 10m (forwards: 2.12 ± 0.14s; backs: 1.98 ± 0.11s), 20m (forwards: 3.71 ± 0.27s; backs: 3.46 ± 0.20s), 30m (forwards: 5.29 ± 0.41s; backs: 4.90 ± 0.33s), 40m (forwards: 6.91 ± 0.61s; backs: 6.33 ± 0.46s) and aerobic capacity (forwards: 453.4 ± 258.8m; backs: 665.0 ± 298.2m) than forwards. Additionally, international players were found to have greater anthropometric and physical qualities in comparison to their WSL counterparts. This study adds to the limited evidence base surrounding the anthropometric and physical qualities of elite women’s rugby league players. Comparative values for anthropometric and physical qualities are provided which practitioners may use to evaluate the strengths and weaknesses of players, informing training programs to prepare players for the demands of women's rugby league.

Sit-to-Stand Power Across the Lifespan: A Cross-Sectional Analysis

Lower-body power measured by a linear position transducer during the sit-to-stand (STS) movement declines with age and may be a predictor of physical disability in older adults. The purpose of this study was to establish normative data for STS power across the lifespan and to determine if differences exist between age cohorts, sexes, and age cohort–sex subgroups. Adults (N = 557) aged 18–89 were divided into five age cohorts and performed the STS connected to a linear position transducer, which calculated power and velocity during the movement. Significantly lower (p < .01) velocity was observed in a younger age cohort in females than males, whereas males saw a significant average power decrement (p < .01) in a younger age cohort than females. STS power norms give clinicians a metric predicting physical disability and may be of particular interest to males as their power production begins to decline at an earlier age.

Effects of the lower jaw position on athletic performance of elite athletes

When an athlete wears a mouthguard, the position of the lower jaw is changed by virtue of the teeth being unable to occlude. Little research is available in in this area, which have indicated both positive impact and no positive impact.ObjectivesThis study aims to explore the influence of the lower jaw position on athletic performance in elite athletes.MethodsA repeated measures study compared two lower jaw positions, the athlete’s normal (habitual) bite and the lower jaw position when the muscles of mastication are at physiological rest (physiological rest bite). 15 athletes completed a medicine ball putt (upper body power), vertical jump (lower body power), sit and reach (composite hamstring flexibility), passive knee flexion (hamstring muscle length) and star excursion balance (stability and balance) tests in each condition.ResultsPaired t-tests showed the physiological rest bite had significant (p<0.05) positive effect on athletic performance for each test. On average the physiological rest bite provided an increase of lower body power (5.8%), upper body power (10%), hamstring flexibility (14%) and balance and stability (4.8%) compared to the habitual bite.ConclusionThis study provides evidence of the need for further research to confirm if the lower jaw position can be optimised for athletic performance in athletes.

Relationships between Linear Sprint, Lower-Body Power Output and Change of Direction Performance in Elite Soccer Players

The aim of this study was to investigate the relationship between linear sprint, power output obtained during a squat and change of direction (COD) performance. Fifteen elite soccer players participated in this study (age = 21.7 ± 0.72 years, body mass = 74.9 ± 9.11 kg, body height = 180.4 ± 7 cm, training experience = 9 ± 1.5 years). To examine these correlations a following battery of tests were carried out: 20-m linear sprint, one-repetition maximum (1RM) squat strength, peak power output obtained during a squat at 50% 1RM and time obtained in two 20-m COD tests with different angles of direction change (90° and 135°). In addition, COD deficits (90°-CODDEF and 135°-CODDEF) for both COD tests were calculated. The Spearman’s rank order correlation showed a nearly perfect statistical relationship between the 90°-COD and the 90°-CODDEF (r = 0.9; p < 0.001). In the case of 90°-CODDEF, there was a large statistical relationship with 135°-CODDEF (r = 0.59; p = 0.021). Moreover, there was a nearly perfect statistical relationship between 135°-COD and 135°-CODDEF (r = 0.91; p < 0.001). The statistically insignificant (p > 0.05) relationship between 20-m linear sprint time, power output obtained during a squat at 50% 1RM, 1RM squat strength level and both COD test, as well as both COD deficits were found. Results of the present study showed that 20-m linear sprinting speed, 1RM squat strength, power output obtained during squat at 50% 1RM and COD ability at 90° and 135° angles, are separate physical qualities. Moreover, it seems that COD deficit provides a more isolated measure of COD ability than the COD tests alone and does not must be limited to a specific angle, but provides knowledge about the COD ability in a range of other angles, at least concerning 90° and 135° COD angles.

Relative Age Effect of Sport Academy Adolescents, a Physiological Evaluation

The relationship between birth quarter distribution and physiological characteristics related to athletic skills, in adolescent sport academy students has not been fully investigated. In a cross-sectional study, we recruited 86 boys and 52 girls aged 12–14 years during their first term at a sport academy school. We measured body size, cardiac size, pulmonary function, body composition, lower body power, cardiorespiratory fitness parameters, and running endurance by standard methods and analyzed these estimates in relation to birth quarter by ANOVA. Birth quarter distribution in our cohort was compared with birth quarter distribution in the same ages in the whole of Sweden and analyzed by logistic regression. The academy had an overrepresentation of students born in the first quartile of the year compared to those born in the last quartile (odds ratio 2.3 (95% CI: 1.1–4.7)). When comparing the physiological characteristics between birth quarters, uniformity is prominent since out of 26 performed physiological and anthropometric tests only four showed statistically significant group differences. We thus believe that the selection process to the sport academy favours athletes with higher chronological age, i.e., a so-called relative age effect is present.