Muscle atrophy and bone loss after 90 days' bed rest and the effects of flywheel resistive exercise and pamidronate: Results from the LTBR study

Skeletal muscle mass and composition during mammalian hibernation

“…For example, hindlimb suspension (Thomason and Booth, 1990), bed rest (Widrick et al, 1997) and denervation (Hornberger et al, 2001) are all accepted models for investigating decreased activity and disuse atrophy. Commonalities amongst these models are a decrease in muscle mass (Musacchia et al, 1983;Thomason et al, 1987), protein concentration (Bajotto and Shimomura, 2006;Larsson et al, 1996) and fiber size (Pellegrino and Franzini, 1963;Rittweger et al, 2005;Wagatsuma et al, 2011). Most studies also show a conversion from slow to fast fiber types (Boonyarom and Inui, 2006) and a decline in muscle strength (Adams et al, 2003;Larsson et al, 1996;Thomason and Booth, 1990).…”

WISE-2005: effect of aerobic and resistive exercises on orthostatic tolerance during 60 days bed rest in women

“…This paper reports the results from a part of an extensive WISE study (for Women International Space Simulation for Exploration) which was conducted to evaluate whether the combination of an aerobic treadmill exercise within LBNP and resistive exercise performed on a Xywheel ergometer prevents physiological deconditioning in women during 60 days of HDBR. Association of a resistive Xywheel exercise to the LBNP/Ex countermeasure was justiWed by the positive eVects obtained on bone and muscle with resistive exercise after a 90-day bed rest study in men (Rittweger et al 2005;Alkner and Tesch 2004). EVects on bone, muscle and other aspects of this study (e.g., eVects on female endocrine responses, aerobic capacity…) will be reported elsewhere.…”

Functional and morphological effects of resistance exercise on disuse-induced skeletal muscle atrophy

“…Among the models of RE most commonly used in disuse atrophic states are flywheel (30)(31)(32)(33)(34), vascular occlusion (VO) (35), and conventional RE consisting of concentric/eccentric or isometric muscle actions (20,36,37). It is important to emphasize that the composition of these types of RE differs in terms of intensity and volume.…”

“…This same research group noted that individuals submitted to lower limb immobilization who performed RE (knee extension) in a flywheel for 5 weeks showed a significant gain of 7.7% in quadriceps volume and maintenance of basal strength (isometric strength at 90° and 120°) when compared with the untrained immobilized group (31). Rittweger et al (33) chronically evaluated the role of flywheel RE in healthy young individuals submitted to bed rest with -6 degrees head-down for 90 days and observed that the trained group showed maintenance of 8.3% of thigh CSA when compared to the control group. Later, these investigators assessed the effect of this model of RE on the same experimental design in terms of vertical jump power 4, 7, 14, 90, and 180 days after 90 days of bed rest and observed that the delta of vertical jump amplitude and peak power after 4 days were -13 cm and -12.9 W/kg reduced in the control group and only -4.2 cm and -4 W/ kg reduced in the trained group.…”

“…In humans, Akima et al (30) evaluated the effects of lower limb RE (leg press) in subjects undergoing 20 days of bed rest in the same experimental conditions as used by Rittweger et al (33). They observed that the trained group showed significant preservation of femoral biceps and semitendinosus muscle CSA (corresponding to approximately 70% of the flexor muscles) compared to the untrained group.…”