Normative Values of Muscle Power using Force Plate Jump Tests in Men Aged 77-101 Years: The Osteoporotic Fractures in Men (MrOS) Study

Therapeutic validity and replicability of power training interventions in older adults: A review using the TIDieR checklist and CONTENT scale

Background

Randomized controlled trials (RCTs) indicate that power training has the ability to improve muscle power and physical performance in older adults. However, power training definitions are broad and previously-established criteria are vague, making the validity and replicability of power training interventions used in RCTs uncertain.

Objective

The aim of this review was to assess whether the power training interventions identified in a previous systematic review (el Hadouchi 2022) are fully described, therapeutically valid, and meet our proposed criteria for power training.

Design

Review.

Methods

Power training interventions used in older adults, previously-identified in a systematic review, were assessed. The completeness of intervention descriptions was evaluated using the Template for Intervention Description and Replication (TIDieR), and therapeutic validity was evaluated using the CONTENT scale in combination with a set of criteria specific for power training.

Results

None of the power training interventions were fully described or met the CONTENT scale's criteria for therapeutic validity. Five out of 14 interventions (35.7 %) met all specific power training criteria.

Conclusions

Power training interventions used in RCTs comparing power training to strength training are poor to moderately described, may not be therapeutically valid, and may not reflect the construct of power training. This makes it difficult for clinicians or researchers to apply or replicate power training interventions reported in RCTs, and begs the question whether the true effects of power training have been estimated.

Referent Values for Commonly Used Clinical Mobility Tests in Black and White Adults Aged 50-95 Years

OBJECTIVE

To estimate referent values for performance on clinical mobility tests conducted amongst racially diverse adults aged 50-95 years in the Southeast US.

DESIGN

This is an observational study of community-dwelling older adults from diverse racial groups who participated in observational and rehabilitative studies conducted from 2011-2019.

SETTING

Rehabilitation clinics around the greater metropolitan Atlanta, Georgia, region.

PARTICIPANTS

A total of 314 adults (N=314; 222 women). Individuals were predominantly Black (n=121) or White (n=164), with some participants from other racial groups (n=29).

INTERVENTIONS

Clinical and demographic data were collected at individual visits for each participant.

MAIN OUTCOME MEASURES

Four Square Step Test (FSST), timed Up and Go (TUG) test, dual TUG test, 6-minute walk test (6MWT), 30-second chair stand, and gait speed were all used as assessments in each cohort.

RESULTS

Performance slowly declines with increasing age, with a sharp drop in the ninth decade for preferred forward, backward, and fast gait speed; backward gait cadence; 6MWT, TUG test, dual-task TUG-Cognitive, and the 360° turn test. Declines were also seen in the eighth and ninth decades in the FSST. Among White participants, there were significant overall differences across age groups except in the assessment variable, preferred gait cadence. For Black individuals, there were significant overall differences across age groups for backward gait speed, fast gait speed, TUG-Cognitive, dual task, 6MWT, FSST, and 30-second chair stand.

CONCLUSIONS

These data enrich current referent values for brief, commonly used clinical tests in a diverse, older Southeast US cohort. These data include representatives of the oldest old cohort. This study will support race- and age-specific fall prevention and mobility-enhancing therapeutic application among older patients in clinical practice.

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.

Lower Leg Power and Grip Strength Are Associated With Increased Fall Injury Risk in Older Men: The Osteoporotic Fractures in Men Study

BACKGROUND

Past research has not investigated both lower-extremity power and upper-extremity strength in the same fall injury study, particularly nonfracture fall injuries.

METHODS

In the Osteoporotic Fractures in Men Study (baseline: N = 5 994; age 73.7 ± 5.9 years; 10.2% non-White), fall injuries (yes/no) were assessed prospectively with questionnaires approximately every 3 years over 9 years. Maximum leg power (Watts) from Nottingham single leg press and maximum grip strength (kg) from handheld dynamometry were assessed at baseline and standardized to kg body weight. Physical performance included gait speed (6-m usual; narrow walk) and chair stands speed.

RESULTS

Of men with ≥1/4 follow-ups (N = 5 178; age 73.4 ± 5.7 years), 40.4% (N = 2 090) had ≥1 fall injury. In fully adjusted repeated-measures logistic regressions, lower power/kg and grip strength/kg had higher fall injury risk (trend across quartiles: both p < .0001), with lower quartiles at significantly increased risk versus highest Q4 except for grip strength Q3 versus Q4. Fall injury risk was 19% higher per 1 standard deviation (SD) lower power/kg (95% confidence interval [CI]: 1.12-1.26) and 16% higher per SD lower grip strength/kg (95% CI: 1.10-1.23). In models including both leg power/kg and grip strength/kg, odds ratios (ORs) were similar and independent of each other and physical performance (leg power/kg OR per SD = 1.13, 95% CI: 1.06-1.20; grip strength/kg OR per SD = 1.11, 95% CI: 1.05-1.17).

CONCLUSIONS

Lower leg power/kg and grip strength/kg predicted future fall injury risk in older men independent of physical performance. Leg power potentially identifies fall injury risk better than grip strength at higher muscle function, though grip strength may be more suitable in clinical/practice settings.

Defining terms commonly used in sarcopenia research: a glossary proposed by the Global Leadership in Sarcopenia (GLIS) Steering Committee

METHODS

The aim of this paper is to define terms commonly related to sarcopenia to enable standardization of these terms in research and clinical settings. The Global Leadership Initiative in Sarcopenia (GLIS) aims to bring together leading investigators in sarcopenia research to develop a single definition that can be utilized worldwide; work on a global definition of sarcopenia is ongoing. The first step of GLIS is to develop the common terminology, or a glossary, that will facilitate agreement on a global definition of sarcopenia as well as interpretation of clinical and research findings.

RESULTS

Several terms that are commonly used in sarcopenia research are defined, including self-reported measures of function and ability; objective physical performance tests; and measures related to muscle function and size.

CONCLUSION

As new methods and technologies are developed, these definitions may be expanded or refined over time. Our goal is to promote this common language to describe sarcopenia and its components in clinical and research settings in order to increase clinical awareness and research interest in this important condition. We hope that the use of common terminology in sarcopenia research will increase understanding of the concept and improve communication around this important age-related condition.

Effectiveness of power training compared to strength training in older adults: a systematic review and meta-analysis

BACKGROUND

Research suggests that muscle power is a more critical determinant of physical functioning in older adults than muscle strength. The objective of this study was to systematically review the literature on the effect of power training compared to strength training in older adults on tests for muscle power, two groups of activity-based tests under controlled conditions: generic tests and tests with an emphasis on movement speed, and finally, physical activity level in daily life.

METHODS

A systematic search for randomized controlled trials comparing effects of power training to strength training in older adults was performed in PubMed, Embase, Ebsco/CINAHL, Ebsco/SPORTDiscus, Wiley/Cochrane Library and Scopus. Risk of bias was assessed using the Cochrane Collaboration Tool, and quality of evidence was evaluated using GRADEpro Guideline Development Tool. Standardized mean differenences (SMD) and 95% confidence intervals (CI) were calculated for outcomes separately using a random effects model.

RESULTS

Fifteen trials and 583 participants were included in the meta-analysis. Results indicated a statistically significant benefit of power training on all reported outcomes (muscle power SMD: 0.99, 95% CI: 0.54 to 1.44, p < 0.001; generic activity-based tests SMD: 0.37, 95% CI 0.06 to 0.68; p = 0.02, activity-based tests emphasizing movement speed SMD: 0.43, 95% CI 0.23 to 0.62, p < 0.001). None of the included studies used physical activity level in daily life as outcome.

CONCLUSIONS

Power training offers more potential for improving muscle power and performance on activity tests in older adults compared to strength training. Future research should assess exercise parameters for power training in older adults. In addition, the validity and reliability of the tests used must be evaluated to establish a standardized test protocol. This protocol should also include measurements of physical activity in daily life.

Relative sit-to-stand power cut-off points and their association with negatives outcomes in older adults

The purposes of this study were: (i) to evaluate the association of sit-to-stand (STS) power and body composition parameters [body mass index (BMI) and legs skeletal muscle index (SMI)] with age; (ii) to provide cut-off points for low relative STS power (STS_rel), (iii) to provide normative data for well-functioning older adults and (iv) to assess the association of low STS_rel with negative outcomes. Cross-sectional design (1369 older adults). STS power parameters assessed by validated equations, BMI and Legs SMI assessed by dual-energy X-ray absorptiometry were recorded. Sex- and age-adjusted segmented and logistic regression analyses and receiver operator characteristic curves were used. Among men, STS_rel showed a negative association with age up to the age of 85 years (− 1.2 to − 1.4%^year−1; p < 0.05). In women, a negative association with age was observed throughout the old adult life (− 1.2 to − 2.0%^year−1; p < 0.001). Cut-off values for low STS_rel were 2.5 W kg⁻¹ in men and 1.9 W kg⁻¹ in women. Low STS_rel was associated with frailty (OR [95% CI] = 5.6 [3.1, 10.1]) and low habitual gait speed (HGS) (OR [95% CI] = 2.7 [1.8, 3.9]) in men while low STS_rel was associated with frailty (OR [95% CI] = 6.9 [4.5, 10.5]) low HGS (OR [95% CI] = 2.9 [2.0, 4.1]), disability in activities of daily living (OR [95% CI] = 2.1 [1.4, 3.2]), and low quality of life (OR [95%CI] = 1.7 [1.2, 2.4]) in women. STS_rel declined with increasing age in both men and women. Due to the adverse outcomes related to STS_rel, the reported cut-off points can be used as a clinical tool to identify low STS_rel among older adults.

The effects of ageing on functional capacity and stretch-shortening cycle muscle power

[Purpose] To examine the effects of age and gender in an ageing population with respect to functional decline and the relationship between muscle power and functional capacity. [Participants and Methods] The cohort (N=154) was subdivided into youngest-old (65–70 years.; n=62), middle-old (71–75 years.; n=46), and oldest-old (76–81 years.; n=46). Measures of mechanical muscle function included countermovement jump height, muscle power, leg strength and grip strength. Functional performance-based measures included heel-rise, postural balance, Timed Up and Go, and gait speed. [Results] The oldest-old performed significantly worse than the middle-old, whereas the youngest-old did not outperform the middle-old to the same extent. Increased contribution of muscle power was observed with increasing age. Males had consistently higher scores in measures of mechanical muscle function, whereas no gender differences were observed for functional capacity. [Conclusion] The age-related decline in functional capacity appears to accelerate when approaching 80 years of age and lower limb muscle power seems to contribute to a greater extent to the preservation of functional balance and gait capacity at that stage. Males outperform females in measures of mechanical muscle function independent of age, while the findings give no support for the existence of gender differences in functional capacity.

Defining an international cut-off of two-legged countermovement jump power for sarcopenia and dysmobility syndrome

We aimed to establish jump power cut-offs for the composite outcome of either sarcopenia (EWGSOP2) or dysmobility syndrome using Asian and Caucasian cohorts. Estimated cut-offs were sex specific (women: < 19.0 W/kg; men: < 23.8 W/kg) but not ethnicity specific. Jump power has potential to be used in definitions of poor musculoskeletal health.

PURPOSE

Weight-corrected jump power measured during a countermovement jump may be a useful tool to identify individuals with poor musculoskeletal health, but no cut-off values exist. We aimed to establish jump power cut-offs for detecting individuals with either sarcopenia or dysmobility syndrome.

METHODS

Age- and sex-matched community-dwelling older adults from two cohorts (University of Wisconsin-Madison [UW], Korean Urban Rural Elderly cohort [KURE], 1:2) were analyzed. Jump power cut-offs for the composite outcome of either sarcopenia defined by EWGSOP2 or dysmobility syndrome were determined.

RESULTS

The UW (n = 95) and KURE (n = 190) cohorts were similar in age (mean 75 years) and sex distribution (68% women). Jump power was similar between KURE and UW women (19.7 vs. 18.6 W/kg, p = 0.096) and slightly higher in KURE than UW in men (26.9 vs. 24.8 W/kg, p = 0.050). In UW and KURE, the prevalence of sarcopenia (7.4% in both), dysmobility syndrome (31.6% and 27.9%), or composite of either sarcopenia or dysmobility syndrome (32.6% and 28.4%) were comparable. Low jump power cut-offs for the composite outcome differed by sex but not by ethnicity (< 19.0 W/kg in women; < 23.8 W/kg in men). Low jump power was associated with elevated odds of sarcopenia (adjusted odds ratio [aOR] 4.07), dysmobility syndrome (aOR 4.32), or the composite of sarcopenia or dysmobility syndrome (aOR 4.67, p < 0.01 for all) independent of age, sex, height, and ethnicity.

CONCLUSION

Sex-specific jump power cut-offs were found to detect the presence of either sarcopenia or dysmobility syndrome in older adults independent of Asian or Caucasian ethnicity.

Jump power, leg press power, leg strength and grip strength differentially associated with physical performance: The Developmental Epidemiologic Cohort Study (DECOS)

BACKGROUND

Weight-bearing jump tests that measure lower-extremity muscle power may be more strongly related to physical performance measures vs. non-weight-bearing leg press power, leg press strength and grip strength. We investigated if multiple muscle function measures differentially related to standard physical performance measures.

MATERIALS/METHODS

In the Developmental Epidemiologic Cohort Study (DECOS; N = 68; age 78.5 ± 5.5 years; 57% women; 7% minorities), muscle function measures included power in Watts/kg (functional, weight-bearing: jump; mechanical: Nottingham power rig; Keiser pneumatic leg press) and strength in kg/kg body weight (Keiser pneumatic leg press; hand-held dynamometry). Physical performance outcomes included 6 m usual gait speed (m/s), usual-paced 400 m walk time (seconds), and 5-repeated chair stands speed (stands/s).

RESULTS

Women (N = 31; 79.8 ± 5.0 years) had lower muscle function and slower gait speed compared to men (N = 25; 78.7 ± 6.6 years), though similar 400 m walk time and chair stands speed. In partial Pearson correlations adjusted for age, sex, race and height, muscle function measures were moderately to strongly correlated with each other (all p < 0.05), though the individual correlations varied. In multiple regression analyses, each muscle function measure was statistically associated with all physical performance outcomes in models adjusted for age, sex, race, height, self-reported diabetes, self-reported peripheral vascular disease and self-reported pain in legs/feet (all p < 0.05). Jump power (β = 0.75) and grip strength (β = 0.71) had higher magnitudes of association with faster gait speed than lower-extremity power and strength measures (β range: 0.32 to 0.58). Jump power (β = 0.56) had a slightly lower magnitude of association with faster 400 m walk time vs. Keiser power_{70% 1-RM} (β = 0.61), and a higher magnitude of association vs. Nottingham power, Keiser strength and grip strength (β range: 0.41 to 0.47). Jump power (β = 0.38) had a lower magnitude of association with chair stands speed than any other power or strength measures (β range: 0.50 to 0.65).

CONCLUSIONS

Jump power/kg and grip strength/kg may be more strongly related to faster gait speed, a standard measure of physical function and vital sign related to disability and mortality in older adults, compared to leg press power/strength. However, jump power/kg had a similar magnitude of association with 400 m walk time as Keiser power_{70% 1-RM}/kg and a lower magnitude of association with faster chair stands speed than the other muscle function measures. Importantly, choice of muscle function measures should carefully reflect the study focus and methodologic considerations, including population.

Bipedal hopping as a new measure to detect subtle sensorimotor impairment in people with multiple sclerosis

BACKGROUND

Bipedal hopping has the potential to detect subtle multiple sclerosis (MS)-related impairments, especially among patients who "pass" typical movement tests. In this narrative review, we outline the biomechanics of bipedal hopping and propose its usefulness as a novel outcome measure for people with MS having mild disability.

METHODS

We summarize articles that (1) examined the biomechanics of jumping or hopping and (2) tested the validity and/or reliability of hopping tests. We consolidated consistencies and gaps in research and opportunities for future development of the bipedal hop test.

RESULTS

Bipedal hopping requires immense power, coordination, balance, and ability to reduce co-contraction; movement components typically affected by MS. These impairments can be measured and differentiated by examining specific variables, such as hop length (power), symmetry (coordination), center of pressure (balance), and coefficient of variability (co-contraction/spasticity). Bipedal hopping challenges these aspects of movement and exposes sensorimotor impairments that may not have been apparent during walking.

CONCLUSIONS

Testing of bipedal hopping on an instrumented walkway may detect and monitor sensorimotor control in people with MS who do not currently present with clinical deficits. Early measurement is imperative for precise rehabilitation prescription to slow disability progression prior to onset of measurable gait impairment.Implications for rehabilitationJumping and hopping tests detect lower limb and balance impairments in children, athletes, and older adults.Bipedal hop test measures multiple domains: power, coordination, balance, and muscle timing.Bipedal hop test may expose subtle sensorimotor impairments in people with multiple sclerosis.Multiple variables measured can discern type of sensorimotor impairment to direct personalized rehabilitation programs.

An age-adapted plyometric exercise program improves dynamic strength, jump performance and functional capacity in older men either similarly or more than traditional resistance training

Power declines at a greater rate during ageing and is more relevant for functional deterioration than either loss of maximum strength or muscle mass. Human movement typically consists of stretch-shortening cycle action. Therefore, plyometric exercises, using an eccentric phase quickly followed by a concentric phase to optimize power production, should resemble daily function more than traditional resistance training, which primarily builds force production capacity in general. However, it is unclear whether older adults can sustain such high-impact training. This study compared the effects of plyometric exercise (PLYO) on power, force production, jump and functional performance to traditional resistance training (RT) and walking (WALK) in older men. Importantly, feasibility was investigated. Forty men (69.5 ± 3.9 years) were randomized to 12-weeks of PLYO (N = 14), RT (N = 12) or WALK (N = 14). Leg press one-repetition maximum (1-RM), leg-extensor isometric maximum voluntary contraction (MVC) and rate of force development (RFD), jump and functional performance were evaluated pre- and post-intervention. One subject in RT (low back pain) and three in PLYO (2 muscle strains, 1 knee pain) dropped out. Adherence to (91.2 ± 4.4%) and acceptability of (≥ 7/10) PLYO was high. 1-RM improved more in RT (25.0 ± 10.0%) and PLYO (23.0 ± 13.6%) than in WALK (2.9 ± 13.7%) (p < 0.001). PLYO improved more on jump height, jump power, contraction time of jumps and stair climbing performance compared to WALK and/or RT (p < 0.05). MVC improved in RT only (p = 0.028) and RFD did not improve (p > 0.05). To conclude, PLYO is beneficial over RT for improving power, jump and stair climbing performance without compromising gains in strength. This form of training seems feasible, but contains an inherent higher risk for injuries, which should be taken into account when designing programs for older adults.

Associations between novel jump test measures, grip strength, and physical performance: the Osteoporotic Fractures in Men (MrOS) Study

BACKGROUND/AIMS

Weight-bearing jump tests measure lower extremity muscle power, velocity, and force, and may be more strongly related to physical performance than grip strength. However, these relationships are not well described in older adults.

METHODS

Participants were 1242 older men (mean age 84 ± 4 years) in the Osteoporotic Fractures in Men (MrOS) Study. Jump peak power (Watts/kg body weight), force (Newton/kg body weight) at peak power, and velocity (m/s) at peak power were measured by jump tests on a force plate. Grip strength (kg/kg body weight) was assessed by hand-held dynamometry. Physical performance included 400 m walk time (s), 6 m usual gait speed (m/s), and 5-repeated chair stands speed (#/s).

RESULTS

In adjusted Pearson correlations, power/kg and velocity moderately correlated with all performance measures (range r = 0.41-0.51; all p < 0.001), while correlations for force/kg and grip strength/kg were weaker (range r = 0.20-0.33; all p < 0.001). Grip strength/kg moderately correlated with power/kg (r = 0.44; p < 0.001) but not velocity or force/kg. In adjusted linear regression with standardized βs, 1 SD lower power/kg was associated with worse: 400 m walk time (β = 0.47), gait speed (β = 0.42), and chair stands speed (β = 0.43) (all p < 0.05). Associations with velocity were similar (400 m walk time: β = 0.42; gait speed: β = 0.38; chair stands speed: β = 0.37; all p < 0.05). Force/kg and grip strength/kg were more weakly associated with performance (range β = 0.18-0.28; all p < 0.05).

CONCLUSIONS/DISCUSSION

Jump power and velocity had stronger associations with physical performance than jump force or grip strength. This suggests lower extremity power and velocity may be more strongly related to physical performance than lower extremity force or upper extremity strength in older men.

Are jumping mechanography assessed muscle force and power, and traditional physical capability measures associated with falls in older adults? Results from the Hertfordshire Cohort Study

OBJECTIVES

To explore associations between measures of lower limb muscle force, velocity and power from jumping mechanography (JM) and simple physical capability (PC) testing, and falls in community dwelling older adults.

METHODS

Participants performed a two-leg countermovement jump on a ground reaction force platform. Jump force, power and velocity were calculated. PC tests were 6m timed-up-and-go (TUG)(sec), grip strength (kg), gait speed (m/s) and chair rise time (secs). Two-three years after JM and PC testing, self-reported falls in the previous year were recorded, and logistic regression analysis used to determine whether JM and PC measures were associated with falls.

RESULTS

Fall and PC data were available for 258 (169 JM) participants. Mean (SD) age at baseline was 75(2.5) years, 50% (n=129) were women and 27% (n=70) had fallen. As power and velocity increased, the odds of being a faller decreased [(odds ratio (OR)=0.91, 95% confidence interval (CI) 0.85,0.98] and (OR=0.20, 95% CI 0.05 0.72) respectively). Whilst grip strength and TUG were associated with falling; relationships were attenuated after adjustment.

CONCLUSIONS

Jumping mechanography-measured muscle power and velocity were associated with lower risk of falls. In this relatively healthy cohort of older adults JM appears to be more sensitive measure of muscle deficits and falls risk than standard PC measures.