1.
Effects of a 12-week, short-interval, intermittent, low-intensity, slow-jogging program on skeletal muscle, fat infiltration, and fitness in older adults: randomized controlled trial.
Ikenaga, M, Yamada, Y, Kose, Y, Morimura, K, Higaki, Y, Kiyonaga, A, Tanaka, H, ,
European journal of applied physiology. 2017;(1):7-15
Abstract
PURPOSE We developed a short-interval, low-intensity, slow-jogging (SJ) program consisting of sets of 1 min of SJ at walking speed and 1 min of walking. We aimed to examine the effects of an easily performed SJ program on skeletal muscle, fat infiltration, and fitness in older adults. METHODS A total of 81 community-dwelling, independent, older adults (70.8 ± 4.0 years) were randomly assigned to the SJ or control group. The SJ group participants were encouraged to perform 90 min of SJ at their anaerobic threshold (AT) intensity and 90 min of walking intermittently per week. Aerobic capacity at the AT and sit-to-stand (STS) scores were measured. Intracellular water (ICW) in the legs was assessed by segmental multi-frequency bioelectrical impedance analysis. Subcutaneous (SAT) and intermuscular (IMAT) adipose tissue and muscle cross-sectional area (CSA) were measured at the mid-thigh using computed tomography. RESULTS A total of 75 participants (37 SJ group, 38 controls) completed the 12-week intervention. The AT and STS improved in the SJ group compared with the controls (AT 15.7 vs. 4.9 %, p < 0.01; STS 12.9 vs. 4.5 %, p < 0.05). ICW in the upper leg increased only in the SJ group (9.7 %, p < 0.05). SAT and IMAT were significantly decreased only in the SJ group (p < 0.01). CONCLUSION The 12-week SJ program was easily performed by older adults with low skeletal muscle mass, improved aerobic capacity, muscle function, and muscle composition in older adults.
2.
Rapid cooling techniques in joggers experiencing heat strain.
Clapp, AJ, Bishop, PA, Muir, I, Walker, JL
Journal of science and medicine in sport. 2001;(2):160-7
Abstract
This study examined subjects that exercised on three occasions in a heated environment (WBGT = 39 degrees C] until they experienced heat strain. Since morbidity and mortality due to heat injury increase with the duration of elevated core temperature, it is important that techniques to lower core temperature be evaluated. Following three exercise sessions, subjects underwent each of three core cooling treatments in random order: 1) Torso immersion in cool water, 2) Hands and feet immersion in cool water, and 3) Sit-in-shade with a 1.5mph breeze provided. Subjects (n=5) consistently reached peak rectal temperatures of 38.8 (+/-0.1) degrees C following each exercise bout in the heated environment. Torso immersion produced a significantly (p<0.05) greater rate of decline in rectal temperature (0.25+/-0.10 degrees C/min) than the hands and feet immersion technique (0.16+/-0.05 degrees C/min) and the sit in the shade technique (0.11+/-0.04 degrees C/min). After only 10 minutes of cooling, the differences among cooling techniques were evident. Similar trends were observed for mean heart rate readings, albeit not significant (p>0.05). It was concluded that rectal temperatures can be reduced rapidly through the use of a cool water torso-immersion technique.