Maximum Power During Vertical Jump and Isometric Knee Extension Torque Alter Mobility Performance: A Cross-Sectional Study of Healthy Individuals

Jumping Motor Skills in Typically Developing Preschool Children Assessed Using a Battery of Tests

The preschool period is characterised by the improvement in motor skills. One of the developmental tasks in children is the ability to jump. Jumping plays an important role in the development of leg strength and balance. It is the gateway to more complex movements. In the physiotherapy clinic, we see a lot of difficulties in jumping performance in 5-7-year-old children. The aim of this study is to present the jumping ability, assessed by the Motor Proficiency Test (MOT) and the G-sensor examination of the vertical countermovement jump (CMJ) and countermovement jump with arms thrust (CMJAT) parameters. A total of 47 children (14 boys and 33 girls) were randomly recruited. The mean age was 5.5 years. The mean height was 113 cm and the mean weight was 19.7 kg. The children were divided into two groups according to their results. Children with low basic motor skills have the greatest difficulty with jumping tasks. In the CMJ jump, the take-off force was lower than in the CMJAT (p = 0.04). Most CMJAT parameters correlate with age, weight, and height. Height correlates most with children's jumping performance. This study may be useful for sport educators and developmental researchers. The topic should be further explored and the CMJ and CMJAT parameters may be established as a basis.

Musculoskeletal Fitness for Identifying Low Physical Function in Older Women

AIMS

This cross-sectional study aimed to analyze the relevance of musculoskeletal fitness for identifying low physical functioning in community-dwelling older women.

METHODS

Sixty-six older women (73.62 ± 8.23 yrs old) performed a musculoskeletal fitness assessment of the upper and lower limbs. A handheld dynamometer was used to evaluate upper-limb muscle strength through a handgrip (HG) test. Lower-limb power and force were assessed from a two-leg countermovement vertical jump (VJ) on a ground reaction force platform. Physical functioning was assessed subjectively using the Composite Physical Function (CPF) questionnaire and objectively by daily step count measured by accelerometry and gait speed/agility assessed by the 8-Foot Up-and-Go (TUG) test. Logistic regressions and ROC curves were carried out to define odds ratios and ideal cutoff values for discriminatory variables.

RESULTS

VJ power showed the ability to identify low physical functioning when evaluated through the CPF (14 W/kg, 1011 W), gait speed/agility (15 W/kg, 800 W), or daily accumulated steps (17 W/kg). Considering that VJ power was normalized for body mass, the increase of 1 W/kg corresponds to a decrease of 21%, 19%, or 16% in the chance of low physical functioning when expressed by these variables, respectively. HG strength and VJ force did not show a capacity to identify low physical functioning.

CONCLUSIONS

The results suggest that VJ power is the only marker of low physical functioning when considering the three benchmarks: perception of physical ability, capacity for mobility, and daily mobility.

Norm Values of Muscular Strength Across the Life Span in a Healthy Swiss Population: The COmPLETE Study

BACKGROUND

Grip strength is used to estimate whole-body strength for health surveillance purposes. Explosive strength is considered important, yet economic measures able to detect early deterioration of neuromuscular capabilities are lacking. Whether handgrip maximum rate of force development (GRFD) or whole-body strength tests are better predictors of lower body power than handgrip maximum strength (GF_max) and their trajectories throughout the life span are unknown.

HYPOTHESIS

GRFD should be more closely related to lower body power than GF_max, and its trajectories over the life span should more closely follow that of lower body power.

STUDY DESIGN

Cross-sectional.

LEVEL OF EVIDENCE

Level 2b.

METHODS

A total of 613 healthy participants aged 20 to 91 years were tested for countermovement jump peak power, GF_max, handgrip rate of force development, and midthigh pull peak force (MTP). Cubic splines and linear models were built for age trajectories, generalized additive models for quintile curves, and linear regression was used to assess predictive quality.

RESULTS

Peak power (P_max) declined linearly to 60% of young adult level, with GRFD, GF_max, and MTP remaining stable up to age 50 years and then declining more sharply to 52% to 71% of young adult levels. Trajectories were similar for male and female participants. GRFD (β = 0.17) and MTP (β = 0.08) were worse predictors of P_max than GF_max (β = 0.24) in models adjusted for age, sex, lean body mass, and vigorous physical activity levels.

CONCLUSION

GRFD was not superior to maximum strength in predicting lower body power. For health surveillance purposes, it therefore appears that GF_max tests are more economical and equally good predictors of lower body explosive strength at older age. The data provided can be used as norm values for healthy subjects.

CLINICAL RELEVANCE

Incorporating countermovement jump testing for early detection of declines in explosive capabilities might be advised.

Mechanical properties of muscles and tendon structures in middle-aged and young men

The purpose of this study was to compare the mechanical properties of muscles and tendon structures for plantar flexor muscles at various strain rates and jump performances using single joint between middle-aged and young men in order to clarify the mechanisms of age-related decline in power output during vertical jump of middle-aged people previously reported. Passive muscle stiffness of the medial gastrocnemius muscle was determined based on passive muscle force and fascicle length during passive stretching at four angular velocities. Active muscle stiffness was calculated based on changes in muscle force and fascicle length during stretching at five angular velocities after submaximal isometric contractions. Maximal elongation and hysteresis of tendon structures were assessed from estimated muscle force—tendon elongation during ramp and ballistic contractions. Two kinds of unilateral jump heights using only ankle joint (no-countermovement and countermovement jumps) were measured. No significant differences in passive and active muscle stiffness, tendon structure properties (except for maximal elongation during ramp contraction), or jump heights were found between middle-aged and young men. The results suggest that the mechanical properties of muscles and tendon structures for plantar flexor muscles and jump performances using only ankle joint do not show age-related changes in middle-aged men.

Considerations for the Design of a Physical Fitness Battery to Assess Adults with Intellectual Disabilities: Preliminary Reference Values for the SAMU DIS-FIT Study

For the assessment of the health-related physical fitness (PF) of individuals with intellectual disabilities (ID), tools designed for people without disabilities have generally been used. Also, the results of these assessments have routinely been compared with the scores obtained by people without ID. The objectives of the present study are to present the rationale for the design of an assessment battery for PF, the so-called SAMU DIS-FIT battery, and to present the results obtained by the participants classified according to age, sex, and level of PF (physical fitness). The selection criteria for the tests that would make up the battery were: (i) utility, (ii) psychometric properties, (iii) easiness and diversity, (iv) simplicity of execution, (v) familiarity and motivation, and (vi) economy of resources. A cross-sectional study was designed to assess the PF of 261 individuals with ID. To interpret the results obtained by the participants, each of the quantitative variables of PF was categorized into three levels: lower-fit, mid-fit, and higher-fit. The findings of this study serve as a first step in establishing PF baseline values for individuals with ID.

Age and sex-related decline of muscle strength across the adult lifespan: a scoping review of aggregated data

Muscle strength is sex-related and declines with advancing age; yet, a comprehensive comparative evaluation of age-related strength loss in human females and males has not been undertaken. To do so, segmented piecewise regression analysis was performed on aggregated data from studies published from 1990 to 2018 and are available in CINAHL, EMBASE, MEDLINE, and PsycINFO databases. The search identified 5613 articles that were reviewed for physical assessment results stratified by sex and age. Maximal isometric and isokinetic 60°·s^-1 knee extension (KE) and knee flexion (KF) contractions from 57 studies and 15 283 subjects (N = 7918 females) had sufficient data reported on females and males for meaningful statistical evaluation to be undertaken. The analysis revealed that isometric KE and KF strength undergo similar rapid declines in both sexes late in the sixth decade of life. Yet, there is an abrupt age-related decline in KE 60°·s^-1 peak torque earlier in females (aged 41.8 years) than males (aged 66.7 years). In the assessment of KF peak torque, an age-related acceleration in strength loss was only identified in males (aged 49.3 years). The results suggest that age-related isometric strength loss is similar between sexes while the characteristics of KE and KF peak torque decline are sex-related, which likely explains the differential rate of age-related functional decline. Novelty Inclusion of muscle strength and torque of KE and KF data from >15 000 subjects. Isometric KE and KF strength loss are similar between sexes. Isokinetic 60°·s^-1 KE torque decline accelerates 25 years earlier in females and female age-related KF peak torque decline does not accelerate with age.

Reference value for the TUGT in healthy older people: A systematic review and meta-analysis

The timed up and go test (TUGT) was recently proposed as a strong predictor of adverse outcomes. Few reviews have been conducted to identify a standard for the TUGT in healthy older people, and the aims of this study were to explore the source of heterogeneity and evaluate the range of reference values for the TUGT in healthy people over 60 years old stratified by age and sex. The VIP, EMBASE, Web of Science and PubMed databases were searched from January 1, 2000, to December 31, 2018. A subgroup analysis and meta-regression were used to assess heterogeneity. Thirty-four eligible studies were included. The mean TUGT results for the total population, males and females in the sample were 9.21 s [95% CI (9.11, 9.31)], 9.33 s [95% CI (7.82, 11.08)] and 8.87 s [95% CI (8.40, 9.38)], respectively. The mean TUGT results for older people in their 60 s, 70 s, and 80 s were 7.91 s [95% CI (6.62, 9.20)], 8.67 s [95% CI (7.23, 10.12)] and 11.68 s [95% CI (8.11, 15.26)], respectively. The meta-regression analysis results showed that the heterogeneity was related to age (P < 0.01). Age affects the results of the TUGT, and it is necessary to take age into consideration when conducting stratified physical evaluations for the evaluation of older people individuals' physical fitness.