al., 2011 ). However, it is not entirely clear whether muscle strength and muscle power are involved in the physical activity levels of older men with COPD. The peripheral muscle dysfunction of the lower limbs observed in older men with COPD is characterized by a reduction in the maximum muscle strength and
María Hernández, Fabrício Zambom-Ferraresi, Pilar Cebollero, Javier Hueto, José Antonio Cascante and María M. Antón
Konstantina Katsoulis, Liza Stathokostas and Catherine E. Amara
After age 65 years, muscle power (the product of force and velocity or force per unit time) declines faster than muscle strength (the ability to produce maximal force), with the rate of power loss reported to be 3.5–6% per year compared with strength losses of 0–1.5% per year ( Clark et al., 2013
Rheanna Bulten, Sara King-Dowling and John Cairney
field tests to assess MF in children, there is still a lack of evidence on their validity. A recent study by King-Dowling et al ( 18 ) assessed the validity of SLJ for predicting peak muscle power as measured by a Wingate test in preschool-aged children (aged 3–5 y). Results of the study showed that SLJ
Michael L. Madigan
The purpose of this study was to investigate agerelated differences in muscle power during a surrogate task of trip recovery. Participants included 10 healthy young men (19–23 years old) and 10 healthy older men (65–83). The task involved releasing participants from a forward-leaning posture. After release, participants attempted to recover their balance using a single step of the right foot. Muscle power at the hip, knee, and ankle of the stepping limb were determined from the product of joint angular velocity and joint torque. Muscle powers during balance recovery followed a relatively consistent pattern in both young and older men, and showed effects of both lean and age. Interestingly, the effects of age did not always involve smaller peak power values in the older men as expected from the well-documented loss of muscle power with aging. Older men exhibited smaller peak muscle power at the knee and larger peak muscle power at the ankle and hip compared to young men. The increases in muscle power at the ankle and hip may result from a neuromuscular adaptation aimed at improving balance recovery ability by compensating for the age-related loss of muscle function.
Eric Maylia, John A. Fairclough, Leonard D.M. Nokes and Michael D. Jones
The purpose of this study was to assess whether measurements of thigh bulk taken with a tape measure would give an indication of muscle power. Eleven male patients, all undergoing unilateral menisectomies, performed exercises of the quadriceps and hamstring muscles during concentric loading at 60°/s. The patients were tested three times over a 12-week period: one day before the operation and 2 and 12 weeks after the operation. Thigh girth was recorded, using a conventional plastic tape measure, 10 cm from the top of the patella in each of the three test sessions. The results of this study demonstrated that muscle power cannot be predicted from thigh girth measurements.
Neil A. Doldo, Matthew J. Delmonico, Jason A. Bailey, Brian D. Hand, Matthew C. Kostek, Karma M. Rabon-Stith, Kalapurakkal S. Menon, Joan M. Conway, Craig R. Carignan and Ben F. Hurley
To determine sex and race differences in muscle power per unit of muscle contraction, knee-extensor muscle power normalized for knee-extensor muscle volume was measured in 79 middle-aged and older adults (30 men and 49 women, age range 50–85 years). Results revealed that women displayed a 38% faster peak movement velocity than men and African Americans had a 14% lower peak movement velocity than Whites of a similar age when expressed per unit of involved muscle (p < .001). As expected, men exhibited greater knee-extensor strength and peak power per unit of muscle than women, but women had a faster knee-extension movement velocity per unit of muscle than men at the same relative strength level. Moreover, African Americans had greater knee-extensor muscle volume than Whites but exhibited lower knee-extensor strength and lower movement velocity per unit of muscle when tested at the same relative strength levels.
Robert C. Manske and George J. Davies
Most patients on an index concentric isokinetic test of the shoulder internal and external rotators have significant torque-acceleration-energy (TAE) deficits.
To assess the effectiveness of rehabilitation on muscle power in patients with shoulder dysfunctions.
Physical therapy clinic.
67, mean age 28.7 ± 12.89 years.
Main Outcome Measures:
Concentric shoulder internal and external rotators measured with arm at 90° of abduction, 90° of elbow flexion. Isokinetic velocities tested: 60°, 180°, and 300°/s.
A paired t test (P < .05) compared the differences from index to discharge test for involved and uninvolved internal and external shoulder rotators. Percentages of TAE deficits involved vs uninvolved on discharge and change in TAE from index to discharge were also analyzed. Significant improvement of the involved shoulder for all velocities for both internal and external rotators was seen. The uninvolved extremity saw statistically significant improvements at all velocities for external rotators yet only at 300°/s for internal rotators. Involved-extremity TAE deficits returned to within 10% on discharge.
The study demonstrated improved muscle power as measured by TAE in shoulder internal and external rotators in a sample of patients treated in an outpatient clinic.
Heydar Sadeghi, Francois Prince, Karl F. Zabjek and Paul Allard
In this study, tasks of the hip in elderly and young gait were identified using principal-component analysis (PCA). Discrepancies between older and younger participants for hip-flexor and -extensor action during stance were also investigated. PCA was applied to the sagittal-hip-muscle-power curves of participants. Three principal components (PCs) were retained for further analysis. A t test revealed that all measures of gait spatiotemporal parameters were significantly lower in the older participants (p < .05). The first PC for both groups extracted the largest variation and described hip-power action during midistance. The second and third PCs in the older participants highlighted the role of the hip extensors and flexors during weight acceptance, late stance, and pull-off. The corresponding PCs for the younger participants were mainly associated with hip-extensor/flexor action during pull-off and weight acceptance. The results indicate that the hip-extensor/flexor muscles are mainly responsible for balance control in elderly gait but contribute to both balance control and propulsion in the gait of younger individuals.
Jill L. McNitt-Gray
Jocelyn F. Hafer, Mark S. Miller, Jane A. Kent and Katherine A. Boyer
-related changes in gait and muscle function compared with males but that high levels of PA would mitigate this effect, and thus, fewer differences would be present between highly active males and females. In agreement with this hypothesis, our results suggest age-related changes in gait mechanics, muscle power