Prevention of bone loss during 56 days of strict bed rest by side-alternating resistive vibration exercise

Abstract

Bed rest is a recognized model for muscle atrophy and bone loss in space flight and in clinical medicine. We hypothesized that whole body vibration in combination with resistive exercise (RVE) would be an effective countermeasure. Twenty healthy male volunteers underwent horizontal bed rest for 56 days and were randomly assigned either to a group that performed RVE 11 times per week or to a group that underwent bed rest only (Ctrl). Bone mineral content (BMC) was assessed by peripheral quantitative computed tomography (pQCT) in the tibia and the radius and by dual x-ray absorptiometry (DXA) in the hip and lumbar spine at baseline and at regular intervals during bed rest and a 12-month follow-up. RVE appeared to protect muscle size and function, and it also prevented bone loss (p-values between <0.001 and 0.01). Bone losses were largest in the distal tibia epiphysis, where BMC declined from 421.8 mg/mm (SD 51.3) to 406.6 mg/mm (SD 52.7) in Ctrl, but only from 411.1 mg/mm (SD 56.6) to 409.6 mg/mm (SD 66.7) in RVE. Most of the BMC losses were recovered by 12-month follow-up. Analyses showed that the epiphyseal cortex, rather than spongiosa, depicted the most pronounced changes during bed rest and recovery. These results suggest that the combined countermeasure applied in this study is effective to prevent bone losses from the tibia. This underlines the importance of mechanical usage for the maintenance of the human skeleton.

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

“…spine, pelvis and legs) [1][2][3]. Evidence [4,5] from bed rest studies, a methodology commonly used to simulate the effects of spaceflight [6], suggests that exercise countermeasures that include highload resistive exercise for the lower limbs and spine would be more effective in reducing bone loss in spaceflight than low load/low impact endurance exercise [1,7,8]. This suggestion corresponds to findings from animal studies [9,10] that loading of bone with larger forces (such as during resistance exercise), leading to greater bone strain [11], generates a greater stimulus for osteogenesis.…”

“…Prior work in the 1st Berlin Bed Rest Study [5,21] has shown that RVE can reduce bone loss during prolonged bed rest. Whilst animal studies may strongly suggest that this countermeasure would be more effective than high-load resistance exercise alone (RE), evidence in support of this hypothesis in humans is lacking.…”

Effects of Sex and Gender on Adaptation to Space: Musculoskeletal Health

“…There is little evidence, however, on whether there is a sex difference in rates of bone loss with unloading or in the rate or magnitude of recovery therefrom. While the effects of bed rest on BMD and/or bone metabolism have been examined separately in men 13,14 and in women, 15,16,17 there have been no human studies that have been statistically powered to make direct sex comparisons. In one 17-week bed rest study that included both men (n = 13) and women (n = 5) at one of 10 sites measured (calcaneus), bone loss was markedly less in women than men.…”

“…6 However, the dual energy x-ray absorptiometry-assessed total hip BMD for women in a 60-day bed rest study 17 revealed a substantial loss at that site, whereas men in a similar study did not have a decrease in total hip bone mineral content. 13 Volumetric BMD and bone geometry of tibial cancellous and cortical compartments have been evaluated after prolonged bed rest using peripheral quantitative computed tomography (pQCT) in men 13,15 and high-resolution pQCT in women. 16 The small gender differences observed in the bone loss rates at those tibial sites are within the reported precision for these pQCT variables.…”

In vivoassessment of the effect of controlled high- and low-frequency mechanical loading on peri-implant bone healing

“…The latter refers to the evidence that HF mechanical loading improves the bone's mechanical properties, thereby promoting its properties to withstand the physiological demands [2]. This makes HF mechanical loading a potent nonpharmacological intervention for osteoporosis, fracture healing and beyond [2,[12][13][14].…”