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Use of elastic energy to improve economy and ease of walking may be important for older adults. The purpose of this investigation was to determine whether baseline (i.e., untrained) stretch-shortening cycle potentiation (SSCP) was associated with potential changes in free-living activity-related energy expenditure (AEE) after supervised exercise training. Sedentary, postmenopausal women (n 5 64) between 60 and 74 years of age were evaluated before and after 16 weeks of combined aerobic and resistance training. Assessments included: (a) body composition (dual-energy X-ray absorptiometry), (b) resting energy expenditure (indirect calorimetry), (c) submaximal and maximal walking (treadmill/indirect calorimetry), (d) total energy expenditure (doubly labeled water), and (e) one repetition maximum performed on an incline leg press and SSCP (calculated as the difference between concentric and countermovement leg press throw). Results indicated that baseline SSCP was related (r = -0.29; p, 0.02) to changes in AEE. However, subjects who possessed a high baseline SSCP did not increase SSCP or AEE, whereas subjects with low to moderate baseline SSCP demonstrated a significant increase in both SSCP (low +0.54 and moderate +0.47m·s-1) and AEE (low +158 and moderate +333 kcal·d-1) post-training (all p less than 0.05). Our findings suggest that among subjects with low to moderate baseline SSCP, 16 weeks of combined aerobic and resistance training can increase SSCP and free-living AEE. However, subjects with high baseline SSCP may require tailored exercise to increase SSCP and possibly AEE. [ABSTRACT FROM AUTHOR]

Hunter, GR, Neumeier, WH, Chandler-Laney, PC, Carter, SJ, Borges, JH, Hornbuckle, LM, Plaisance, EP, and Fisher, G. Ratings of perceived exertion during walking predicts endurance independent of physiological effort in older women. J Strength Cond Res 34(5): 1340-1344, 2020 This study aimed to determine whether ratings of perceived exertion (RPE) and physiological effort at different exercise intensities relate to exercise endurance. Ninety-eight sedentary women (older than 60 years) completed 3 submaximal locomotion tasks: (a) stair climbing, (b) flat walking at 2 mph, and (c) grade walking at 2 mph. Maximal treadmill endurance was measured at least 3 days before the submaximal tests.Oxygen uptakewas measured during all tests, and RPE were collected for the submaximal tasks. Ratings of perceived exertion during moderate-intensity exercise (walking on the flat at 43% VO2max, partial R=20.35, p,<0.01), but not higher intensity exercise (grade walk at 59%VO2max, p = 0.49, and stair climbing at 67% VO2max, p = 0.17), were related to endurance even after adjusting for aerobic capacity and physiological effort (composite of maximal heart rate, ventilation, and respiratory exchange ratio). However, physiological effort was significantly related to endurance for the higher intensity exercise (both grade walk and stair climbing partial R .>; −0.24, p ,< 0.02). Similar to previous findings that subjective ratings of fatigue at rest were related to RPE during low/moderateintensity exercise, but not higher intensity exercise, these data further support Ekkekakiss dual-mode hypothesis that cognitive factors influence RPE during low∕moderate-intensity exercise. A practical application is that the coach and personal trainer should know that physiological effort seems to play a greater role in influencing endurance than RPE as intensity of exercise increases [ABSTRACT FROM AUTHOR]

The article discusses the development of an experimental model to study interaction of achilles tendon length and leg strength while running. Topics discussed include measurement of tendon length through magnetic resonance imaging, energy required for isometric contractions and statistical analysis based on stretch shortening cycle potential (SSCP).

The article discusses a study which was aimed to determine the optimal frequency of combined aerobic and resistance training for improving muscular strength (MS), cardiovascular fitness (CF), and functional tasks (FTs) in women older than 60 years. The study included 63 women who were randomly assigned to 1 of 3 exercise training groups. The study found no significant differences for MS, CF, or FT outcomes between groups.

The purpose of this study was to determine the effect resistance training has on metabolic economy during typical activities of daily living in a geriatric population. Twenty-nine men and women (age: 66.7 ± 4.4 years, body mass: 72.3 ± 11.9 kg) participated in a 26-week heavy-resistance training program. Before and after training, heart rate and expiratory gases were measured for subjects performing 3 tasks that would mimic common everyday activities encountered by this population: (a) walking (WLK) at 3 miles per hour (4.8 km·h-1), (b) carrying a box (CAR) to simulate holding a bag of groceries with 1 hand (30% of maximal isometric strength) while walking at 2 miles per hour (3.2 km·h-1), and (c) climbing stairs (STR). No time by gender interaction was observed for the WLK, CAR, and STR activities; consequently, the values for men and women were pooled. Both strength and fat-free mass increased significantly (p < 0.001) after the training protocol, whereas body mass remained constant. Oxygen cost decreased significantly by 6% (p < 0.05) only for CAR, whereas the respiratory exchange ratio decreased significantly (p < 0.05) for both WLK (0.84-0.81) and STR (0.87-0.83), and heart rate decreased significantly (p < 0.05) only for CAR. After the resistance training program, subjects also reported a significant decrease (p < 0.05) in perceived exertion during performance of all functional task test conditions. These results suggest that a heavy-resistance training program might affect exercise economy during daily tasks and improve ease of physical activity, thereby providing a possible mechanism for increasing quality of life in an older and geriatric population. [ABSTRACT FROM AUTHOR]

The purposes of this study were to (a) determine whether structural differences in triceps surae muscle-tendon complex and walking economy exist between 14 African American and 19 Caucasian sedentary women and (b) determine whether muscle-tendon parameters are associated with walking economy. African American and Caucasian subjects were matched on body weight, height, and body composition. Muscle-tendon parameters were determined by magnetic resonance imaging and walking economy was evaluated at 4.8 km ·h-1. Medial gastrocnemius and total triceps surae muscle shape were different across ethnicity despite no ethnic differences in plantar flexion strength or in maximal cross-sectional area for any triceps surae muscles. African American women had shorter gastrocnemius muscles and longer tendons and performed walking more economically. Tendon length was the only variable related to walking economy. No ethnic differences were observed in walking economy after adjusting for tendon length. Data show gastrocnemius tendon length is related to level walking and longer gastrocnemius tendons may partly explain more economical walking in African American women. These preliminary findings indicate the structure of the muscle-tendon complex could be a factor partially accounting for reported ethnic differences in certain types of athletic-related performance. [ABSTRACT FROM AUTHOR]

The purpose of this study was to determine heart rate (HR, b·min-1) response during competitive match play of 6 men who were skilled wheelchair (WC) tennis players. Each participant completed an arm crank ergometer test that measured HR via a telemetry device and O2 via open circuit spirometry from rest until fatigue (O2peak). Each athlete participated in 2 competitive singles matches during which HRs were recorded in 5-second intervals and O2 was estimated using the corresponding HR values recorded during the arm ergometer tests. Data analysis revealed an average playing intensity of 69.4 ± 8.9% of HRpeak and 49.9 ± 14.5% of O2peak. In conclusion, it is recommended that skilled adult WC tennis players perform off-court aerobic conditioning as part of their training program, because the intensity of a competitive WC tennis match is sufficiently high enough to stress the cardiovascular system. [ABSTRACT FROM AUTHOR]

Understanding whether metabolic factors are predictive of weight gain is important for developing strategies for prevention of weight gain. Recent research has shown that sleeping and resting energy expenditure are not predictive of weight gain. However, exercise endurance, muscular strength, 31P MRS muscle metabolic economy, and maximum oxygen uptake are independently related to weight gain. Activity-related energy expenditure and the time spent in physical activity are also related to weight gain, with low physical activity explaining approximately 77% of weight gain at 1 year. In addition, weight maintainers spend 80 minutes per day, whereas weight gainers spend less than 20 minutes per day in physical activity equivalent to an intensity of about 4 METS. It is proposed that strength, aerobic fitness, and physical activity are important factors for reducing the rate of weight gain. Although further research is required, these results are suggestive that weight maintenance programs will be more successful if some relatively high-intensity training is included to complement large amounts of low to moderate intense physical activity. [ABSTRACT FROM AUTHOR]

The StairMaster 4000 PT is a popular step ergometer which provides a submaximal test protocol (SM Predicted Vo2max) for the prediction of Vo2max (ml-kg-1min-1). The purpose of this study was to evaluate the SM Predicted Vo2max protocol by comparing it to results from a Vo2max treadmill test in 20 young healthy women aged 20-25 years. Subjects were 10 step-trained (ST) women who had performed aerobic activities and exercised on a step ergometer for 20-30 minutes at least 3 times per week for the past 3 months, and 10 non-step-trained (NST) women who had performed aerobic activities no more than twice a week during the past 3 months and had no previous experience on a step ergometer. The SM Predicted Vo2max protocol used 2 steady state heart rates between approximately 115-150 b-min-1 to estimate Vo2max. The Bruce maximal treadmill protocol (Actual Vo2max) was used to measure Vo2max by open circuit spirometry. Each subject performed both tests within a 7-day period. The means and standard deviations for the Actual Vo2max tests were 39.8 ± 6.1 ml-kg-1min-1 for the ST group, 37.6 ± 6.3 ml-kg-1min-1 for the NST group, and 38.7 ± 6.2 ml-kg-Lmin-1 for the Total group (N = 20); and for the SM Predicted Vo2max tests, means and standard deviations were 40.78 ± 14.0 ml-kg-1-min-1, 30.9 ± 4.8 ml-kg-1min-1 and 35.9 ± 11.4 ml-kg-1.min-1. There was no significant difference (p > 0.05) between the means of the Actual Vo2max and SM Predicted Vo2max test for the Total group (N = 20) or the ST group (n = 10), but a significant difference (p < 0.05) was shown for the NST group. The coefficient of determination (R2) and standard error of estimate (SEE) for the SM Predicted Vo2max and Actual Vo2max tests were R2 = 0.18, SEE = 5.72 ml-kg-1-min-1 for the Total group; R2 = 0.00, SEE = 6.68 ml-kg-1.min-1 for the NST group; and R2 = 0.33, SEE = 5.32 ml-kg-1.min-1 for ST group. In conclusion, the SM Predicted Vo2max test has acceptable accuracy for the ST group, but significantly underpredicted the NST group by almost 7 ml; and, as demonstrated by the high SEEs, it has a low level of precision for both ST and NST subjects. [ABSTRACT FROM AUTHOR]