Highly Demanding Resistive Vibration Exercise Program is Tolerated During 56 Days of Strict Bed-Rest

Abstract

Several studies have tried to find countermeasures against musculoskeletal de-conditioning during bed-rest, but none of them yielded decisive results. We hypothesised that resistive vibration exercise (RVE) might be a suitable training modality. We have therefore carried out a bed-rest study to evaluate its feasibility and efficacy during 56 days of bed-rest. Twenty healthy male volunteers aged 24 to 43 years were recruited and, after medical check-ups, randomised to a non-exercising control (Ctrl) group or a group that performed RVE 11 times per week. Strict bed-rest was controlled by video surveillance. The diet was controlled. RVE was performed in supine position, with a static force component of about twice the body weight and a smaller dynamic force component. RVE comprised four different units (squats, heel raises, toe raises, kicks), each of which lasted 60 - 100 seconds. Pre and post exercise levels of lactate were measured once weekly. Body weight was measured daily on a bed scale. Pain questionnaires were obtained in regular intervals during and after the bed-rest. Vibration frequency was set to 19 Hz at the beginning and progressed to 25.9 Hz (SD 1.9) at the end of the study, suggesting that the dynamic force component increased by 90 %. The maximum sustainable exercise time for squat exercise increased from 86 s (SD 21) on day 11 of the BR to 176 s (SD 73) on day 53 (p = 0.006). On the same days, post-exercise lactate levels increased from 6.9 mmol/l (SD2.3) to 9.2 mmol/l (SD 3.5, p = 0.01). On average, body weight was unchanged in both groups during bed-rest, but single individuals in both groups depicted significant weight changes ranging from - 10 % to + 10 % (p < 0.001). Lower limb pain was more frequent during bed-rest in the RVE subjects than in Ctrl (p = 0.035). During early recovery, subjects of both groups suffered from muscle pain to a comparable extent, but foot pain was more common in Ctrl than in RVE (p = 0.013 for plantar pain, p = 0.074 for dorsal foot pain). Our results indicate that RVE is feasible twice daily during bed-rest in young healthy males, provided that one afternoon and one entire day per week are free. Exercise progression, mainly by progression of vibration frequency, yielded increases in maximum sustainable exercise time and blood lactate. In conclusion, RVE as performed in this study, appears to be safe.

Evidence for an additional effect of whole-body vibration above resistive exercise alone in preventing bone loss during prolonged bed rest

“…Sample size estimates based upon data from an earlier bed rest study [5,23] suggested that for the comparison between RVE and control, six subjects were necessary per group and that for the comparison between RVE and RE, nine subjects per group were required. Based on psychological advice, subjects were paired into "room-mates" prior to the beginning of the study.…”

Resistive vibration exercise attenuates bone and muscle atrophy in 56 days of bed rest: biochemical markers of bone metabolism

“…Twenty male subjects underwent 8 weeks of strict bed rest with a subsequent 12-month follow-up recovery period. The bed-rest protocol, as well as inclusion and exclusion criteria, is discussed in detail elsewhere [27]. In brief, subjects were randomly allocated to either a group that remained inactive (control, CTRL group; N=10; age (mean(SD))=33.4(6.6)years; height=185(7)cm; weight=79.4(9.7)kg) or a group that underwent a wholebody resistive vibration exercise countermeasure program (RVE group; N=10; age=32.6(4.8)years; height=183(9)cm, weight=81.7(14.4)kg) using the Galileo Space exercise device (Novotec Medical, Pforzheim, Germany).…”

“…The exercise regime targeted the lower leg muscle groups with resistive loading and neuromuscular stimuli via wholebody vibration applied at the feet [28,29]. The countermeasure exercise protocol is described in detail elsewhere [27]. In brief, the subjects were placed in supine position ( Fig.…”

Strength, size and activation of knee extensors followed during 8 weeks of horizontal bed rest and the influence of a countermeasure

“…With Rittweger et al (2006) we speculated that vibration in combination with relatively short lasting resistive exercise might be a suitable alternative gravityindependent training modality to prevent bone loss and at the same time preserve neuromuscular function during simulated microgravity. Under ambulant conditions, vibration has an anabolic eVect on trabecular and cortical bone in animals and humans (Rubin et al 2001;Ward et al 2004) but elicits only a comparatively small amount of energy turnover (Rittweger et al 2000) and was found to have no training eVect on voluntary muscle strength indices in young healthy subjects (de Ruiter et al 2003).…”