J Appl Physiol, 2013; 115(5): 586-96, PMID: 23813530
Hypertrophy in the cervical muscles and thoracic discs in bed-rest?
Year: 2013
Belavy DL, Miokovic T, Armbrecht G, Felsenberg D
Charite Universitatsmedizin Berlin.
Abstract
The impact of prolonged bed-rest on the cervical and upper thoracic spine is unknown. In the 2nd Berlin BedRest Study (BBR2-2), 24 male subjects underwent 60d bed-rest and performed either no exercise, resistive exercise or resistive exercise with whole-body vibration. Subjects were followed for 2-years after bed-rest. On axial cervical magnetic resonance images from the skull to T3, the volume of the semi-spinalis capitis, splenius capitis, spinalis cervicis, longus capitis, longus colli, levator scapulae, sternocleidomastoid, middle and posterior scalenes and anterior scalenes were measured. Disc height, anteroposterior width and volume were measured from the C2/3 to T6/7 on sagittal images. The volume of all muscles, with the exception of semi-spinalis capitis, increased during bed-rest (p<0.025). There were no significant differences between the groups for changes in the muscles. Increased upper and mid-thoracic spine disc height and volume (p<0.001) was seen during bed-rest and disc height increases persisted at least 6-months after bed-rest. Increases in thoracic disc height were greater (p=0.003) in the resistive vibration exercise group than in control. On radiological review, two subjects showed new injuries to the mid-lower thoracic spine. One of these subjects reported a mid-thoracic pain incident during maximal strength testing before bed-rest and the other after countermeasure exercise on day-3 of bed-rest. We conclude that bed-rest is associated with increased disc size in the thoracic region and increases in muscle volume at the neck. The exercise device needs to be modified to ensure load is distributed in a more physiological fashion.Keywords: morphology; uncovertebral joint; magnetic resonance imaging; space- flight; microgravity
GID: 3237; Last update: 09.07.2013
