scholarly journals Eccentric contraction-induced muscle injury does not change walking economy in older adults

2011 ◽  
Vol 27 (1) ◽  
pp. 55-65 ◽  
Author(s):  
Mandy Gault ◽  
Richard Clements ◽  
Mark Willems

Eccentric contraction-induced muscle injury does not change walking economy in older adultsThe aim of the study was to examine whether self-selected walking speed during downhill treadmill walking by older adults would result in muscle injury and changes in physiological responses during level walking. Twenty-six participants (age: 67 ± 4 yrs; height: 1.69 ± 0.09 m; body mass: 74.9 ± 13.1kg) were assigned to level (n = 11, 30 min, 0%) or downhill walking (n=15, 30 min, -10%) at a self-selected walking speed. Self-selected walking speed and exercise intensity were similar for both groups (level: 4.2±0.4 km·hr-1, 42±6% VO2max; downhill: 4.6±0.6 km·hr-1, 44±15% VO2max). After 48-hours, downhill walking had reduced maximal voluntary isometric force of the m. quadriceps femoris (-15%, P<0.001), indicative of muscle injury, but no changes were observed for walking economy, minute ventilation, heart rate and respiratory exchange ratio during level walking. For older adults, downhill walking at a selfselected walking speed causes muscle injury without any detrimental effect on walking economy. Regular downhill walking at a self-selected walking speed by older adults is an eccentric endurance activity that may have the potential to improve cardiovascular fitness and muscle strength.

2010 ◽  
Vol 42 ◽  
pp. 48
Author(s):  
Jennifer A. Schrack ◽  
Eleanor M. Simonsick ◽  
Paulo H.M. Chaves ◽  
Luigi Ferrucci

Author(s):  
D. A. Cunningham ◽  
P. A. Rechnitzer ◽  
A. P. Donner

ABSTRACTAn intervention trial with regular physical activity was carried out to test the hypothesis that walking speed is related to the level of cardiovascular fitness (maximal oxygen uptake). Earlier research has demonstrated that when VO2 max is held constant in a multiple regression analysis the association between walking speed and age (29–65 y) is eliminated. To describe the association between self-selected speeds of walking, and level of cardiovascular fitness, 63 men age 60 to 65 were studied before and after a 1 year program of exercise training. VO2 max was determined on a motor driven treadmill. A test of self-selected walking pace was administered over a 240 m indoor course. The men were asked to walk at 3 paces considered by the subjects to be rather slow, normal, and fast, respectively. They were randomly assigned with stratification for white and blue collar occupation to a program of exercise training (n = 33) or control (n = 27). The training program consisted of walking or jogging for 30 min three times per week for one year. After the training program the exercise group increased their VO2 max (9.5%) and their normal walking speed (1.29 to 1.43 m.s−1) significantly compared to the controls. A program of exercise endurance training will result in an increase in the speed of self-selected pace.


2018 ◽  
Vol 74 (10) ◽  
pp. 1598-1604 ◽  
Author(s):  
Melissa M Markofski ◽  
Kristofer Jennings ◽  
Kyle L Timmerman ◽  
Jared M Dickinson ◽  
Christopher S Fry ◽  
...  

Abstract Background Essential amino acids (EAA) and aerobic exercise (AE) acutely and independently stimulate skeletal muscle protein anabolism in older adults. Objective In this Phase 1, double-blind, placebo-controlled, randomized clinical trial, we determined if chronic EAA supplementation, AE training, or a combination of the two interventions could improve muscle mass and function by stimulating muscle protein synthesis. Methods We phone-screened 971, enrolled 109, and randomized 50 independent, low-active, nonfrail, and nondiabetic older adults (age 72 ± 1 years). We used a 2 × 2 factorial design. The interventions were: daily nutritional supplementation (15 g EAA or placebo) and physical activity (supervised AE training 3 days/week or monitored habitual activity) for 24 weeks. Muscle strength, physical function, body composition, and muscle protein synthesis were measured before and after the 24-week intervention. Results Forty-five subjects completed the 24-week intervention. VO2peak and walking speed increased (p < .05) in both AE groups, irrespective of supplementation type, but muscle strength increased only in the EAA + AE group (p < .05). EAA supplementation acutely increased (p < .05) muscle protein synthesis from basal both before and after the intervention, with a larger increase in the EAA + AE group after the intervention. Total and regional lean body mass did not change significantly with any intervention. Conclusions In nonfrail, independent, healthy older adults AE training increased walking speed and aerobic fitness, and, when combined with EAA supplementation, it also increased muscle strength and EAA-stimulated muscle protein synthesis. These increases occurred without improvements in muscle mass.


2013 ◽  
Vol 29 (2) ◽  
pp. 188-193 ◽  
Author(s):  
Hanatsu Nagano ◽  
Rezaul K. Begg ◽  
William A. Sparrow ◽  
Simon Taylor

Although lower limb strength becomes asymmetrical with age, past studies of aging effects on gait biomechanics have usually analyzed only one limb. This experiment measured how aging and treadmill surface influenced both dominant and nondominant step parameters in older (mean 74.0 y) and young participants (mean 21.9 y). Step-cycle parameters were obtained from 3-dimensional position/time data during preferred-speed walking for 40 trials along a 10 m walkway and for 10 minutes of treadmill walking. Walking speed (young 1.23 m/s, older 1.24 m/s) and step velocity for the two age groups were similar in overground walking but older adults showed significantly slower walking speed (young 1.26 m/s, older 1.05 m/s) and step velocity on the treadmill due to reduced step length and prolonged step time. Older adults had shorter step length than young adults and both groups reduced step length on the treadmill. Step velocity and length of older adults’ dominant limb was asymmetrically larger. Older adults increased the proportion of double support in step time when treadmill walking. This adaptation combined with reduced step velocity and length may preserve balance. The results suggest that bilateral analyses should be employed to accurately describe asymmetric features of gait especially for older adults.


Author(s):  
Carlos Rodriguez-Lopez ◽  
Julian Alcazar ◽  
Jose Losa-Reyna ◽  
JuanManuel Carmona-Torres ◽  
Aurora Maria Cruz-Santaella ◽  
...  

AbstractThis study investigated the acute responses to volume-load-matched heavy-load (80% 1RM) versus light-load (40% 1RM) power-oriented resistance training sessions in well-functioning older adults. Using a randomized cross-over design, 15 volunteers completed each condition on a leg press. Neuromuscular (maximal isometric force and rate of force development) and functional performance (power during sit-to-stand test), lactate, and muscle damage biochemistry (creatine kinase, lactate dehydrogenase and C-reactive protein serum concentration) were assessed pre- and post-exercise. Performance declines were found after heavy-load (Cohen’s d effect size (d); maximal isometric force=0.95 d; rate of force development=1.17 d; sit-to-stand power =0.38 d, all p<0.05) and light-load (maximal isometric force=0.45 d; rate of force development=0.9 d; sit-to-stand power=1.17 d, all p<0.05), while lactate concentration increased only after light-load (1.7 d, p=0.001). However, no differences were found between conditions (all p>0.05). Both conditions increased creatine kinase the day after exercise (marginal effect=0.75 d, p<0.001), but no other blood markers increased (all, p>0.05). Irrespective of the load used, power training induced non-clinically significant decreases in sit-to-stand performance, moderate declines in maximal isometric force, but pronounced decreases in the rate of force development. Furthermore, the metabolic stress and muscle damage were minor; both sessions were generally well tolerated by well-functioning older adults without previous experience in resistance training.


2017 ◽  
Vol 98 ◽  
pp. 209-216 ◽  
Author(s):  
Caitlin N. Suire ◽  
Erez Eitan ◽  
Nancy Chiles Shaffer ◽  
Qu Tian ◽  
Stephanie Studenski ◽  
...  

2015 ◽  
Vol 49 (0) ◽  
Author(s):  
Daniella Pires Nunes ◽  
Yeda Aparecida de Oliveira Duarte ◽  
Jair Lício Ferreira Santos ◽  
Maria Lúcia Lebrão

OBJECTIVE To validate a screening instrument using self-reported assessment of frailty syndrome in older adults.METHODS This cross-sectional study used data from the Saúde, Bem-estar e Envelhecimento study conducted in Sao Paulo, SP, Southeastern Brazil. The sample consisted of 433 older adult individuals (≥ 75 years) assessed in 2009. The self-reported instrument can be applied to older adults or their proxy respondents and consists of dichotomous questions directly related to each component of the frailty phenotype, which is considered the gold standard model: unintentional weight loss, fatigue, low physical activity, decreased physical strength, and decreased walking speed. The same classification proposed in the phenotype was utilized: not frail (no component identified); pre-frail (presence of one or two components), and frail (presence of three or more components). Because this is a screening instrument, “process of frailty” was included as a category (pre-frail and frail). Cronbach’s α was used in psychometric analysis to evaluate the reliability and validity of the criterion, the sensitivity, the specificity, as well as positive and negative predictive values. Factor analysis was used to assess the suitability of the proposed number of components.RESULTS Decreased walking speed and decreased physical strength showed good internal consistency (α = 0.77 and 0.72, respectively); however, low physical activity was less satisfactory (α = 0.63). The sensitivity and specificity for identifying pre-frail individuals were 89.7% and 24.3%, respectively, while those for identifying frail individuals were 63.2% and 71.6%, respectively. In addition, 89.7% of the individuals from both the evaluations were identified in the “process of frailty” category.CONCLUSIONS The self-reported assessment of frailty can identify the syndrome among older adults and can be used as a screening tool. Its advantages include simplicity, rapidity, low cost, and ability to be used by different professionals.


2021 ◽  
Vol 13 ◽  
Author(s):  
Robert Stojan ◽  
Navin Kaushal ◽  
Otmar Leo Bock ◽  
Nicole Hudl ◽  
Claudia Voelcker-Rehage

Driving is an important skill for older adults to maintain an independent lifestyle, and to preserve the quality of life. However, the ability to drive safely in older adults can be compromised by age-related cognitive decline. Performing an additional task during driving (e.g., adjusting the radio) increases cognitive demands and thus might additionally impair driving performance. Cognitive functioning has been shown to be positively related to physical activity/fitness such as cardiovascular and motor coordinative fitness. As such, a higher fitness level might be associated with higher cognitive resources and may therefore benefit driving performance under dual-task conditions. For the first time, the present study investigated whether this association of physical fitness and cognitive functioning causes an indirect relationship between physical fitness and dual-task driving performance through cognitive functions. Data from 120 healthy older adults (age: 69.56 ± 3.62, 53 female) were analyzed. Participants completed tests on cardiovascular fitness (cardiorespiratory capacity), motor coordinative fitness (composite score: static balance, psychomotor speed, bimanual dexterity), and cognitive functions (updating, inhibition, shifting, cognitive processing speed). Further, they performed a virtual car driving scenario where they additionally engaged in cognitively demanding tasks that were modeled after typical real-life activities during driving (typing or reasoning). Structural equation modeling (path analysis) was used to investigate whether cardiovascular and motor coordinative fitness were indirectly associated with lane keeping (i.e., variability in lateral position) and speed control (i.e., average velocity) while dual-task driving via cognitive functions. Both cardiovascular and motor coordinative fitness demonstrated the hypothesized indirect effects on dual-task driving. Motor coordinative fitness showed a significant indirect effect on lane keeping, while cardiovascular fitness demonstrated a trend-level indirect effect on speed control. Moreover, both fitness domains were positively related to different cognitive functions (processing speed and/or updating), and cognitive functions (updating or inhibition), in turn, were related to dual-task driving. These findings indicate that cognitive benefits associated with higher fitness may facilitate driving performance. Given that driving with lower cognitive capacity can result in serious consequences, this study emphasizes the importance for older adults to engage in a physically active lifestyle as it might serve as a preventive measure for driving safety.


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