Measures Of Muscle Power Research Articles

The Increased Effectiveness of Loaded Versus Unloaded Plyometric Jump Training in Improving Muscle Power, Speed, Change of Direction, and Kicking-Distance Performance in Prepubertal Male Soccer Players.

To examine the effects of loaded (LPJT) versus unloaded plyometric jump training (UPJT) programs on measures of muscle power, speed, change of direction (CoD), and kicking-distance performance in prepubertal male soccer players. Participants (N = 29) were randomly assigned to a LPJT group (n = 13; age = 13.0 [0.7]y) using weighted vests or UPJT group (n = 16; age = 13.0 [0.5]y) using body mass only. Before and after the intervention, tests for the assessment of proxies of muscle power (ie,countermovement jump, standing long jump); speed (ie,5-, 10-, and 20-m sprint); CoD (ie,Illinois CoD test, modified 505 agility test); and kicking-distance were conducted. Data were analyzed using magnitude-based inferences. Within-group analyses for the LPJT group showed large and very large improvements for 10-m sprint time (effect size [ES] = 2.00) and modified 505 CoD (ES = 2.83) tests, respectively. For the same group, moderate improvements were observed for the Illinois CoD test (ES = 0.61), 5- and 20-m sprint time test (ES = 1.00 for both the tests), countermovement jump test (ES = 1.00), and the maximal kicking-distance test (ES = 0.90). Small enhancements in the standing long jump test (ES = 0.50) were apparent. Regarding the UPJT group, small improvements were observed for all tests (ES = 0.33-0.57), except 5- and 10-m sprint time (ES = 1.00 and 0.63, respectively). Between-group analyses favored the LPJT group for the modified 505 CoD (ES = 0.61), standing long jump (ES = 0.50), and maximal kicking-distance tests (ES = 0.57), but not for the 5-m sprint time test (ES = 1.00). Only trivial between-group differences were shown for the remaining tests (ES = 0.00-0.09). Overall, LPJT appears to be more effective than UPJT in improving measures of muscle power, speed, CoD, and kicking-distance performance in prepubertal male soccer players.

Effect of the Menopausal Transition on Physical Performance: A Longitudinal Study

Low muscle strength and decline in the power are associated with low walking speed and with mobility limitations, disabilities and falls among older populations. Whether menopause per se accelerates decline in physical performance in women and in this way contributes to functional limitations in later years remains controversial. PURPOSE: The aim of this study was to examine changes in physical performance in women aged 47 to 55 following the menopausal transition. METHODS: This longitudinal study is a part of the Estrogenic Regulation of Muscle Apoptosis study. Women aged 47 to 55 were randomly selected from the Finnish National Registry (n=6878) and perimenopausal women (n=228) were followed until postmenopausal. The baseline menopausal status was defined based on menstrual cycle diary and follicle stimulating hormone (FSH) level. The progression of menopausal transition was followed at three-to-six months’ intervals for early perimenopausal and late perimenopausal women, respectively. When FSH >30 IU/l was recorded, the measurement was repeated within two-to-four weeks and if FSH was determined in two consecutive blood samples to be elevated and no bleeding had occurred in past 6 months participant was considered to be postmenopausal. To capture a comprehensive understanding of the physical performance, measures of muscle power (vertical jump), muscle strength (grip and knee extension), aerobic capacity (6min walking distance), and walking speed were carried out. RESULTS: A significant decline in hand grip force for -2.9 % (95%CI -4.5, -1.1; d=0.20) in knee extension force for -3.1% (95%CI -4.8, -1.3; d=0.23) and in vertical jumping height for -3.24 % (95CI -4.6, -1.7; d=0.28) was observed following the menopausal transition. Walking distance significantly increased for 1.9 % (95%CI 1.2, 2.7, d=0.38) while in walking speed changes were 0.24 % (95%CI -1.1, 1.6; d=0.02) non-significant. CONCLUSIONS: The menopausal transition influences muscle strength and power, whereas the influence on mobility/walking was less evident and may follow after. Supported by the funding from the European Union’s Horizon 2020 research and innovation Programme under the Marie Sklodowska-Curie grant agreement No675003, and by the Academy of Finland (ERMA study grant agreement 275323).

Road to the Olympics: physical fitness of medalists of the Canoe Sprint Junior European and World Championship events over the past 20 years.

In this article we aimed to find out whether there is a difference in physiological, anthropometric and power variables between medalists in junior international Championship events (MJCH) and the remaining members of the national team (NT) in flat water canoe sprint. Sixty male junior kayakers from Slovak NT were tested annually between years 1995 and 2016. Sixteen of them won at least one medal (gold, silver or bronze) at junior international Championship. Exercise capacity assessment on treadmill running (TR) and kayak ergometer (KE), anthropometric and muscle power measurements were performed between years 1995 and 2016. MJCH were on average by 10% better in TR speed and KE power output at VO2max than the rest of NT (19.72±0.8 vs. 18±1.0 km.h-1, P<0.01, ES=1.84; 206.6±21.5 vs. 182.3±25.5 W, P<0.01, ES=0.99, respectively). Similarly mean maximal power in bench press and bench pull was higher in MJCH (522.9±72.0 vs. 464.3±69.0 W, P<0.01; ES=0.84; 629.15±63.3 vs. 571.6±58.7 W, P<0.01; ES=0.96, respectively). These data show that an athlete has to be on average by 10% better in physical fitness than the rest of NT to take podium position at canoe sprint junior international Championship. Prosperous juniors are further successful at senior Championship events and Olympics. We assume that high level of physical fitness in junior age is not a guarantee but a prerequisite for a successful future career.

The SPAIRE Technique Allows Sparing of the Piriformis and Obturator Internus in a Modified Posterior Approach to the Hip

The Sparing Piriformis and Internus, Repair Externus (SPAIRE) technique allows a muscle sparing mini-posterior approach to the hip. We present in this article a description of an adaptation of the familiar posterior approach (PA) in which the only tendon released is obturator externus. Termed SPAIRE, this muscle sparing technique enables preservation of the piriformis tendon and conjoint insertion of obturator internus and the gemelli. The technical description allows for safe and reliable replication by any surgeon familiar with the posterior approach (PA) to the hip without reliance on additional equipment, and without compromising the ability to convert into a more extensile approach. This technical description and brief discussion of rationale outlines the ongoing work of the authors in developing the SPAIRE technique as part of the spectrum of the posterior approach to the hip. The senior author now uses this technique routinely for total hip replacements and hemiarthroplasty. Patients are mobilised with no postoperative restrictions whatsoever. Other potential advantages include improved gait, more anatomical restoration of hip function, and enhanced stability. Projects have been initiated in our unit to objectively assess the possible clinical advantages relating to use of the SPAIRE technique using gait analysis, objective measurement of muscle power and studies of hip stability.

Myostatin antibody (LY2495655) in older weak fallers: a proof-of-concept, randomised, phase 2 trial

Myostatin inhibits skeletal muscle growth. The humanised monoclonal antibody LY2495655 (LY) binds and neutralises myostatin. We aimed to test whether LY increases appendicular lean body mass (aLBM) and improves physical performance in older individuals who have had recent falls and low muscle strength and power. In this proof-of-concept, randomised, placebo-controlled, double-blind, parallel, multicentre, phase 2 study, we recruited patients aged 75 years or older who had fallen in the past year from 21 investigator sites across Argentina, Australia, France, Germany, Sweden, and the USA. Eligible patients had low performance on hand grip strength and chair rise tests, tested with the procedure described by Guralnik and colleagues. Participants were stratified by country, age, hand grip strength, and performance on the chair rise test, and were randomly assigned (1:1) by a computer-generated random sequence to receive subcutaneous injections of placebo or 315 mg LY at weeks 0 (randomisation visit), 4, 8, 12, 16, and 20, followed by 16 weeks observation. The primary outcome was change in aLBM from baseline to 24 weeks. We measured physical performance as secondary outcomes (four-step stair climbing time, usual gait speed, and time to rise five times from a chair without arms, or with arms for participants unable to do it without arms) and exploratory outcomes (12-step stair climbing test, 6-min walking distance, fast gait speed, hand grip strength, and isometric leg extension strength). Efficacy analyses included all randomly assigned patients who received at least one dose and had a baseline and at least one subsequent measure. The primary analysis and all other tests of treatment effect (except physical performance tests) were done at a two-sided alpha level of 0·05. Tests of treatment effect on physical performance tests were done at a pre-specified two-sided alpha level of 0·1. This trial is registered with ClinicalTrials.gov, number NCT01604408. Between June 19, 2012, and Dec 12, 2013, we screened 365 patients. 99 were randomly assigned to receive placebo and 102 to receive LY. Treatment was completed in 85 (86%) of patients given placebo and in 82 (80%) given LY. At 24 weeks, the least-squares mean change in aLBM was -0·123 kg (95% CI -0·287 to 0·040) in the placebo group and 0·303 kg (0·135 to 0·470) in the LY group, a difference of 0·43 kg (95% CI 0·192 to 0·660; p<0·0001). Stair climbing time (four-step and 12-step tests), chair rise with arms, and fast gait speed improved significantly from baseline to week 24 with differences between LY and placebo of respectively -0·46 s (p=0·093), -1·28 s (p=0·011), -4·15 s (p=0·054), and 0·05 m/s (p=0·088). No effect was detected for other performance-based measures. Injection site reactions were recorded in nine (9%) patients given placebo and in 31 (30%) patients given LY (p<0·0001), and were generally mild, and led to treatment discontinuation in two patients given LY. Our findings show LY treatment increases lean mass and might improve functional measures of muscle power. Although additional studies are needed to confirm these results, our data suggest LY should be tested for its potential ability to reduce the risk of falls or physical dependency in older weak fallers. Eli Lilly and Company.

Usefulness and limitations of single-slice computed tomography analysis at the third lumbar region in the assessment of sarcopenia

In the previous issue of Critical Care, Moisey and colleagues [1] report that sarcopenia has potential to serve as a predictor for mortality, discharge disposition, and ICU utilization. Sarcopenia may be mitigated by adequate nutrition supply and early rehabilitation, and so identification of patients with ICU-acquired weakness, who could benefit from rehabilitation, is of fundamental importance [2]. Sarcopenia diagnosis is based on estimation of muscle mass. Whole-body imaging methods like computed tomography (CT) and magnetic resonance imaging (MRI) can precisely measure muscle mass, but limitations of these modalities led to new tools for daily practice. The European Working Group on Sarcopenia in Older People (EWGSOP) recommends the use of dual-energy x-ray absorptiometry (DXA) as an alternative [3]. Nowadays, single-slice CT image analysis, which was used in the study by Moisey and colleagues, is becoming a popular alternative. Validation of this technique was previously assessed by comparing the single-slice CT analysis at the third lumbar (L3) region with DXA, which is not the gold standard [4]. Measurement errors related to DXA might affect these validation results. Although Shen and colleagues [5] compared single-slice CT analysis and whole-body MRI, they reported results for the fourth-fifth lumbar region, not for the L3 region. Moreover, this study was conducted among healthy subjects and this limited the generalization of results for the ICU setting. The EWGSOP recommends the measurement of muscle power, function, and mass for a sarcopenia diagnosis [3]. As muscle function and power data of patients were not reported in the present article, we do not know whether all participants were accurately classified as sarcopenic.

S.P.19 Using the Motor Function Measure (MFM) in the assessment of children with Charcot–Marie–Tooth (CMT)1A; strengths and limitations

Abstract Developing and testing assessment modalities for children with varying neuromuscular disorders is a challenge that we are all facing in an attempt to ensure the most effective tools for clinical and research use. The problems faced by children with CMT tend to differ quite widely from children with other neuromuscular disorders due to the preponderance of peripheral symptoms. At Great Ormond Street Hospital we currently have a large cohort of 50 children with CMT1A. We have for several years attempted to find assessments that cover the wide range of problems encountered, in terms of strength, foot deformity, hand function and difficulty with activities of daily living. To this end, we assessed 25 children with a confirmed diagnosis of CMT1a with an age range of 3 years 4 months to 16 years 2 months, using the full MFM 32. Other tests included timed 10 m, grip strength measured by myometry, MRC% and a questionnaire on activities of daily living adapted from the Paediatric Evaluation of Disability Inventory (PEDI). The total MFM percentage correlated well with the other parameters. The MFM is split into three domains, D1 standing and transfers, D2 Axial and proximal motor function, D3 distal motor function. It was found that all the children scored 100% on domain D2, Axial and proximal function which would be expected in a peripheral neuropathy. The children varied most notably in Domain D3, distal motor function, not necessarily due to age or directly related to grip strength. Domain D1 correlated with measurement of muscle power. It was therefore felt that the MFM could be equally efficacious in functional testing without including the Domain D2 and the total percentage calculated accordingly.

Reproducibility of measures of leg muscle power, leg muscle strength, postural sway and mobility in people with Parkinson's disease

Muscle power, muscle strength and postural sway are considered to be determinants of fall risk and gait in Parkinson's disease (PD) and potential targets for therapeutic trials. However, the potential usefulness of these tests as outcome measures depends on their reproducibility in the PD population. Therefore, measures of leg muscle power, leg muscle strength, postural sway and mobility were taken on two occasions 1week apart in 31 people with PD. Measures of muscle power, muscle strength and mobility were found to be very reliable (intraclass correlation coefficients (ICC3,1 0.50–0.97)) and showed good agreement, i.e. small measurement error. Postural sway measures showed poor reliability (ICC3,1 0.04–0.51) and agreement, especially in the presence of disabling dyskinesia. The moderate to high reproducibility of leg muscle power, muscle strength and mobility measures in people with PD confirm their suitability as outcomes measures in clinical and research settings. Further research into the clinical measurement of postural sway in people with PD is warranted, especially in individuals with dyskinesia.

Potência muscular e capacidade de sprints repetidos em jogadores de futebol DOI: 10.5007/1980-0037.2010v12n4p255

Muscle power is one of the most important physical qualities of soccer player performance and needs to be maintained during a match. Thus, the aim of this study was to investigate the levels of muscle power in soccer players before and after performing repeated sprints (RS), and the association between power and RS performance. Twenty soccer players from the under-20 category aged 18-20 years participated in this study. The study consisted of the execution of vertical jumps, execution of RS, new execution of vertical jumps, and collection of blood samples. The continuous jump (CJ) test was performed on a piezoelectric force platform for the measurement of muscle power and the RAST test was used to evaluate RS ability. No significant difference in the levels of muscle power was observed after RS (p=0.57). Significant differences were observed in the first to fifth sprint times (p&lt; 0.01), but not between the fifth and sixth sprint (p=0.06). CJ height before RS was correlated with first sprint time (r=-0.62, p&lt; 0.01), best sprint time (r=-0.60, p&lt; 0.01), and average sprint time (r= -0.54, p&lt;0.01). In conclusion, the soccer players studied showed no significant reduction in muscle power after RS. A decrease in performance was observed from the first to the fifth sprint, but not between the fifth and sixth sprint. The muscle power of soccer players was a determinant factor to perform one maximum sprint, as well as successive sprints.

The effect of a training program combined with augmented afferent feedback from the feet using shoe insoles on gait performance and muscle power in older adults: a randomised controlled trial

Background. Aged-related loss of afferent feedback of the feet plays an important role in gait performance. Although strength, balance and gait training can significantly improve the muscle power and functional abilities of older individuals, it remains unclear whether training effects can be enhanced by augmenting afferent feedback from the feet adding shoe insoles complementary to conventional training.Objective. The current study investigated the effect of physical exercise combined with wearing MedReflex® shoe insoles on the gait performance and muscle power in older adults.Methods. Twenty-eight independent living, older adults aged 65–91 years were randomly assigned to either an insole group (IG; n = 14) or a training group (TG; n = 14). Further 14 subjects matched to the IG and TG were recruited as a control group (CG; n = 14) (no exercise). The IG and TG completed the same training program consisting of aerobic exercises, progressive resistance strength training and stretching exercises twice per week for 12 weeks, whereas, the IG wore the insoles during everyday life and during training sessions. Assessments included the Falls Efficacy Scale – International (FES-I), gait analysis and muscle power measurements of the knee and ankle joint at pre- and post-training.Results. There were significant time × group interactions in walking speed, step length and in several muscle power measurements. The positive effects of gait parameters ranged between 1% and 12% and between 1% and 8% and the trend to improvements of muscle power ranged between 15–79% and 20–79% for the IG and TG, respectively. The IG and TG did not differ significantly in their improvements. The CG showed a trend to deteriorations between 0% and −5% for gait parameters and between −4% and −14% for muscle power. No significant change in FES-I score occurred in neither groups.Conclusions. The results of this study provide evidence of significant improvements in gait performance and muscle power after a conventional training program in independent living, older adults. However, there is no additional effect of long-term adaptation of gait caused by wearing insoles concurrent to physical training.

Association between vitamin D receptor gene polymorphisms, falls, balance and muscle power: results from two independent studies (APOSS and OPUS)

Fall prevention is a key strategy for reducing osteoporotic fractures. We investigated the association between vitamin D receptor (VDR) polymorphisms and reported falls in postmenopausal women. Bsm1 polymorphisms were associated with falls, balance and muscle power measurements. These results may explain some of the excess fracture risk associated with VDR in some studies. Fall prevention is a key strategy for reducing osteoporotic fractures. It has been suggested that vitamin D supplementation may reduce the incidence of falls by reducing body sway and increasing muscle power. The vitamin D receptor gene is a well-studied candidate gene for osteoporosis. We investigated the association between VDR polymorphisms and reported falls in postmenopausal women. Falls data were collected in two separate population cohorts. Five polymorphisms of the VDR gene were analysed (Cdx-2, Fok-1, BsmI, Taq1 and Apa1) in the Aberdeen Prospective Osteoporosis Screening Study (APOSS) cohort. Results found in APOSS were then validated in an independent cohort--the Osteoporosis and Ultrasound (OPUS) study (Bsm1 and Fok1 only), where muscle power and balance were also measured. Carriers of the 'B' allele (Bsm1) showed an increased risk for falls. In APOSS, this was statistically significant for visit 3 multiple falls (p = 0.047) and for recurrent falls (p = 0.043). Similar results were found in OPUS for visit 1 falls (p = 0.025) and visit 1 multiple falls (p = 0.015). Bsm1 polymorphisms were also associated with balance and muscle power measurements. In conclusion, these results demonstrate an association between the Bsm1 polymorphism and risk of falling that may explain some of the excess fracture risk associated with VDR in some studies.

Range of Motion and Quadriceps Muscle Power After Early Surgical Treatment of Acute Combined Anterior Cruciate and Grade-III Medial Collateral Ligament Injuries

Early operative treatment of combined anterior cruciate and medial collateral ligament injuries has frequently led to motion complications and slow quadriceps muscle power gains. The purpose of the present study was to evaluate the effect of early repair or nonoperative treatment of a concomitant medial collateral ligament injury on range of motion of the knee and quadriceps muscle strength in patients with combined injuries. Forty-seven consecutive patients with combined anterior cruciate and grade-III medial collateral ligament injuries were randomized into two groups. The medial collateral ligament was repaired in Group I (n = 23) and was treated nonoperatively in Group II (n = 24). In both groups, the torn anterior cruciate ligament was treated with early reconstruction. The patients were evaluated on the basis of sequential range-of-motion measurements, the one-leg-hop test, and isokinetic muscle power measurements at the time of follow-up, and the findings were compared between the two treatment groups. All patients achieved full knee extension. At all follow-up intervals the flexion deficit was greater in the group that had been managed with surgical repair of both ligaments, but the difference was significant only at six weeks (100 degrees compared with 112 degrees; p = 0.009), twelve weeks (119 degrees compared with 128 degrees; p = 0.043), and thirty-six weeks (130 degrees compared with 136 degrees; p = 0.011) after the operation. The difference between the groups was not significant at fifty-two weeks (132 degrees compared with 137 degrees) or 104 weeks (134 degrees compared with 137 degrees). The quadriceps muscle power deficit at fifty-two weeks was 30.7% in the group that had been managed with combined repair and 20.5% in the group that had been managed with anterior cruciate ligament reconstruction only (p = 0.015). At 104 weeks, the deficits were 14.4% and 9.7%, respectively (p = 0.2). Early operative treatment of combined anterior cruciate and medial collateral ligament injuries is possible without increased long-term mobilization complications. The rehabilitation period is long, and aggressive physiotherapy is recommended. However, nonoperative treatment of the torn medial collateral ligament allows faster restoration of flexion and quadriceps muscle power. Our results favor nonoperative treatment of the torn medial collateral ligament in patients with combined injuries.

The effect of a foot gymnastic exercise programme on gait performance in older adults: A randomised controlled trial

Background. Aged-related loss of ankle dorsiflexion range of motion (ROM) and toe plantarflexor strength play an important role in gait performance. Further, conventional strength, balance and gait training can significantly improve the lower extremity muscle power and functional abilities of older individuals. It remains unclear, however, whether training effects can be enhanced by augmenting ankle ROM and toe plantarflexor strength complementary to training. Objective. This study investigated the effect of physical exercise combined with foot gymnastics on the gait performance in older adults.Methods. Fifty-six independent living, older adults aged 66-91 years were randomly assigned to either foot gymnastics group (FG;n - 28) or training group (TG;n = 28). Further, 14 subjects were integrated as a control group (CG;n = 14) (no exercise). The FG and TG completed the same training program consisting of aerobic exercises, progressive resistance strength training and stretching exercises twice per week for 12 weeks, whereas the FG performed additional foot gymnastic exercises at the end of the training session and a 10-min foot gymnastics home-program daily. Assessments included the Falls Efficacy Scale - International (FES-I), Expanded Timed Get-up-and-Go test (ETGUG), gait analysis and muscle power measurements of the knee and ankle joint at pre- and post-training.Results. No significant change in FES-I score occurred in either group. The FG showed a significant improvement of ankle ROM. There were significant time x group interactions in walking speed, step length, in several muscle power measurements and in ETGUG. The positive effects of gait parameters ranged between 1 and 11% and between 2 and 12%, of muscle power between 14 and 34% and 14 and 46% and of ETGUG were 10 and 8% for the FG and TG, respectively. The FG and TG did not differ significantly in their improvements. The CG showed a trend to deteriorations between 0 and -6% for gait parameters, between -4 and - 14% for muscle power and 0% for ETGUG.Conclusions. The results of this study provide evidence of significant improvements in gait performance, muscle power and ETGUG after a conventional training program in independent living, older adults. However, there is no additional effect on physical performance after foot gymnastic exercises.

THE RELIABILITY OF THE FITRODYNE AS A MEASURE OF MUSCLE POWER

The FitroDyne is a device that attaches to conventional resistance-training equipment to measure speed of movement, from which muscle power is calculated. The aim of this study was to quantify the repeatability of the measurement of muscle power with the FitroDyne during squat jump and biceps curl exercises. Thirty male subjects completed 3 trials, each consisting of 6 squat jumps and 6 biceps curls of increasing loads. Upper body and lower body maximum power was predicted from the force-velocity curves derived from the range of weights used for each trial. Maximum power measurements of a squat jump (range, 911–1,673 W) and biceps curl (range, 45–110 W) had intraclass correlation coefficients (ICC) of R = 0.97 (95% CI, 0.95–0.98) and R = 0.97 (95% CI, 0.95–0.98), respectively. The limits of agreement for the squat jump and biceps curl trials were 217 ± 96 W and 0.11 ± 13.90 W, respectively. It may be concluded that muscle power can be measured with a high degree of reliability with the FitroDyne. The limits of agreement need to be considered when data are interpreted.

Upper and Lower Limb Muscle Power Relationships in Mobility-Limited Older Adults

Lower limb muscle power impairments are modifiable factors underlying mobility limitations in older adults. This study examined relationships between upper and lower limb muscle power and their role in predicting mobility performance among community-dwelling older adults. A cross-sectional analysis was conducted. Participants included 37 mobility-limited adults (24 women, 13 men), aged 65 to 93 years. Measures included upper (elbow extension) and lower limb (double leg press) one repetition maximum (1RM), and muscle power at both 40% and 70% one repetition maximum. Physical performance measures included stair climb time, the Short Physical Performance Battery, and 4-meter walk time. Factors commonly mediating the relationship between impairments and physical performance were analyzed as covariates. Participants had a mean age of 76 years, had five chronic medical conditions, and manifested moderate mobility limitations. Although the associations between the upper and lower limbs were strong (p <.001), the magnitude of association was greater for power (r =.88-.89) as compared to strength (r =.69). Multivariate regression analyses revealed consistently strong relationships between limb muscle power and mobility performance measures. Substituting upper for lower limb power within these models did not materially weaken the relationships. Muscle power appears to be a more generalized attribute between the upper and lower limbs than is muscle strength, suggesting that mechanisms underlying velocity of movement, as opposed to force production, may be important factors underlying muscle power in elderly persons. Additionally, upper limb muscle power measures may serve as a useful surrogate measure of limb power having implications for clinicians and researchers.

The Reliability of the FitroDyne as a Measure of Muscle Power

The FitroDyne is a device that attaches to conventional resistance-training equipment to measure speed of movement, from which muscle power is calculated. The aim of this study was to quantify the repeatability of the measurement of muscle power with the FitroDyne during squat jump and biceps curl exercises. Thirty male subjects completed 3 trials, each consisting of 6 squat jumps and 6 biceps curls of increasing loads. Upper body and lower body maximum power was predicted from the force-velocity curves derived from the range of weights used for each trial. Maximum power measurements of a squat jump (range, 911- 1,673 W) and biceps curl (range, 45-110 W) had intraclass correlation coefficients (ICC) of R = 0.97 (95% CI, 0.95-0.98) and R = 0.97 (95% CI, 0.95-0.98), respectively. The limits of agreement for the squat jump and biceps curl trials were -17 +/- 96 W and 0.11 +/- 13.90 W, respectively. It may be concluded that muscle power can be measured with a high degree of reliability with the FitroDyne. The limits of agreement need to be considered when data are interpreted.

The effect of a foot gymnastic exercise programme on gait performance in older adults: A randomised controlled trial

Background. Aged-related loss of ankle dorsiflexion range of motion (ROM) and toe plantarflexor strength play an important role in gait performance. Further, conventional strength, balance and gait training can significantly improve the lower extremity muscle power and functional abilities of older individuals. It remains unclear, however, whether training effects can be enhanced by augmenting ankle ROM and toe plantarflexor strength complementary to training.Objective. This study investigated the effect of physical exercise combined with foot gymnastics on the gait performance in older adults.Methods. Fifty-six independent living, older adults aged 66–91 years were randomly assigned to either foot gymnastics group (FG; n = 28) or training group (TG; n = 28). Further, 14 subjects were integrated as a control group (CG; n = 14) (no exercise). The FG and TG completed the same training program consisting of aerobic exercises, progressive resistance strength training and stretching exercises twice per week for 12 weeks, whereas the FG performed additional foot gymnastic exercises at the end of the training session and a 10-min foot gymnastics home-program daily. Assessments included the Falls Efficacy Scale – International (FES-I), Expanded Timed Get-up-and-Go test (ETGUG), gait analysis and muscle power measurements of the knee and ankle joint at pre- and post-training.Results. No significant change in FES-I score occurred in either group. The FG showed a significant improvement of ankle ROM. There were significant time × group interactions in walking speed, step length, in several muscle power measurements and in ETGUG. The positive effects of gait parameters ranged between 1 and 11% and between 2 and 12%, of muscle power between 14 and 34% and 14 and 46% and of ETGUG were 10 and 8% for the FG and TG, respectively. The FG and TG did not differ significantly in their improvements. The CG showed a trend to deteriorations between 0 and −6% for gait parameters, between −4 and −14% for muscle power and 0% for ETGUG.Conclusions. The results of this study provide evidence of significant improvements in gait performance, muscle power and ETGUG after a conventional training program in independent living, older adults. However, there is no additional effect on physical performance after foot gymnastic exercises.

Fidedignidade inter e intradias de um teste de potência muscular

Com o envelhecimento há rápida e relevante perda de potência muscular (PM), prejudicando a autonomia e a qualidade de vida, tornando conveniente avaliar a PM. O objetivo do estudo foi determinar a fidedignidade inter e intradias de um teste simples de PM, realizado em uma carga previamente individualizada. Avaliamos 18 jovens adultos saudáveis, sendo 12 mulheres, inexperientes quanto a exercícios de fortalecimento. Determinou-se inicialmente 1RM com medida simultânea da velocidade e da potência (Fitrodyne, Bratislava), no exercício remada alta, até a altura mesoesternal na posição ortostática, obtendo-se ainda a carga na qual se conseguia a maior PM. Na semana seguinte, por cinco dias consecutivos, eles realizaram em quatro dias 2x2 repetições e em um dia 10x2 repetições (3s de intervalo entre as repetições), o mais rápido possível na fase concêntrica, com a carga de PM. Comparando os resultados pela ANOVA para medidas repetidas e teste de Bonferroni, verificou-se que a PM máxima não diferia - médias entre 262 e 267W (p = 0,69). Para a variabilidade dos dados individuais, encontraram-se valores de 3 e 8%, respectivamente, para o coeficiente de variação (CV) e para a média da variação dos resultados pela média dos indivíduos M-m/X. Nas dez séries consecutivas os valores ficaram entre 242 e 263W, somente identificando-se diferenças entre as séries 1 e 4 e 6 (p &lt; 0,05). Excluindo-se os dados da primeira série (cinco dos 18 avaliados tiveram valores excepcionalmente baixos nela), as diferenças desaparecem (p = 0,13). Dados da variabilidade individual demonstraram 6 e 20%, respectivamente, para CV e M-m/X, nas dez séries consecutivas. Os autores concluem que a PM máxima obtida em um teste simples apresenta alta fidedignidade inter e intradias e variabilidade relativamente baixa, quando comparadas com outras mensurações freqüentemente usadas em ciências do exercício. Esse teste pode ser recomendado para medidas de PM em programas voltados para a saúde e a aptidão física, nos quais a utilização de materiais e protocolos mais sofisticados pode ser inapropriada ou inviável.

Nutritional status of patients with amyotrophic lateral sclerosis: relation to the proximity of death

Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease characterized by progressive muscle atrophy and weakness. Although dysphagia is a universal feature of this illness, the nutritional and metabolic status of ALS patients has received little attention. We performed serial measurements of muscle power, body composition, energy expenditure, nitrogen balance, and dietary intake on ALS patients on three occasions over 6 mo in the General Clinical Research Center of the University of Kentucky Medical Center. Data were analyzed in reference to the time of death. Regression analysis demonstrated progressive decreases in body fat, lean body mass, muscle power, and nitrogen balance and an increase in resting energy expenditure as death approached. The changes in body composition were greater in males. Energy and protein consumption averaged 84% and 126% of the recommended dietary allowances, respectively, but did not correlate with complaints of dysphagia. We conclude that ALS patients have a chronically deficient intake of energy and recommended augmentation of energy intake rather than the consumption of high-protein nutritional supplements.

The Nature of the Vertical Jump Test and the Standing Broad Jump

Abstract The jump-reach test and standing broad jump were investigated as tests of muscle power. The criterion used was the power lever. An analysis of the variance components of the two jump tests revealed that each test involved a large proportion of specific variance. Of the common factor variance muscle power appeared to be only one component. A multi-dimensional factor, jumping ability, was important to both the jump-reach test and standing broad jump. These tests appeared to have limited application as measures of muscle power.