atrophy; bed rest; muscle volume; countermeasure exercise; postero-lateral hip; lower-limb
610 Medizin und Gesundheit
As part of the Berlin Bed Rest Study (BBR) and 2nd Berlin Bed Rest Study (BBR2-2), this work investigated the pattern of muscle atrophy of the postero-lateral hip and lower limb musculature during prolonged bed-rest and the effectiveness of two different exercise countermeasures- resistive exercise alone and resistive exercise with whole body vibration, in preventing muscle atrophy.
For the BBR, 20 healthy male subjects underwent 56 days of horizontal bed-rest and were assigned to either an inactive control group (CTR) or resistive vibration exercise group (VRE). For BBR2-2, 24 healthy male subjects underwent 60 days of 6 degrees head-down-tilt (HDT) bed-rest and were assigned to a control group (CTR), resistive vibration exercise group (RVE) or resistive exercise alone group (RE). Magentic resonance imaging (MRI) of the hip and thigh were taken prior to, during and at the end of bed-rest. Volume of the postero-lateral hip and lower limb musculature were calculated and the rate of muscle atrophy and the effect of countermeasure exercises examined.
During bed-rest, the CTR group demonstrated differential rates of muscle volume loss (p<0.0001). The fastest rates of atrophy were seen in the triceps surae (medial gastrocnemius, lateral gastrocnemius, soleus), mono-articular knee extensors (vastii), mono-articular hip extensors and quadratus femoris, an external rotator of the hip and the hamstring muscles. The other postero-medial and postero-lateral muscles of the foot/ankle in addition to the adductor magnus were also strongly affected during bed-rest. The antero-medial hip muscles and anterior tibial muscles were comparatively less affected by bed-rest. Different rates of atrophy were also seen amongst some muscle synergists. For example, the heads of triceps surae and heads of the hamstring muscle group demonstrated different rates of atrophy, the vastii demonstrated a faster rate of atrophy than rectus femoris and upper gluteus maximus atrophied faster than lower gluteus maximus and gluteus medius.
Countermeasure exercise reduced/prevented muscle atrophy in the triceps surae, vastii and gluteal muscles but was less effective for the hamstring muscles, postero-medial and postero-lateral muscles of the foot/ankle and the adductor muscles. The addition of whole body vibration to resistive exercise did not have an additional effect for the variables examined in this work.
In conclusion, a short-duration resistive exercise program with or without whole-body vibration can be effective in reducing the impact of prolonged bed-rest on postero-lateral hip and lower extremity muscle volume loss during bed-rest.
PDF-Datei von FUDISS_thesis_000000098352
Falls Ihr Browser eine Datei nicht öffnen kann, die Datei zuerst herunterladen und dann öffnen.