Healey E L, Burden A M, McEwan I M, Fowler N E
Primary Care Musculoskeletal Research Centre, Primary Care Sciences, Keele University, Staffordshire, ST5 5BG, UK.
Clin Biomech (Bristol). 2008 Jul;23(6):721-6. doi: 10.1016/j.clinbiomech.2008.02.011. Epub 2008 Apr 9.
Stature reductions in asymptomatic individuals, caused by a set load, are lower later in the day when stature is in the trough of diurnal variation; hence most stature reduction investigations are conducted in the morning. Recent evidence suggests that it is not the reductions in stature, but the recovery of stature, that is of greatest importance. The aim of this investigation was to establish whether stature recovery is also affected by time of day and to determine if any differences exist between a chronic low back pain and asymptomatic group.
Eleven chronic low back pain participants (age=32.8 SD 7.9 yrs, mass=74.4 SD 14.2 kg and height=1.73 SD 0.07 m) and 11 asymptomatic participants (age=31.0 SD 6.3 yrs, body mass=72.6 SD 11.5 kg and height=1.76 SD 0.09 m) underwent two 20 min loaded walking tasks (10% body mass), one in the morning (09:00) and one in the afternoon (14:00), followed by a 20 min unloaded recovery period. Measurements of stature were obtained throughout.
The asymptomatic group experienced significantly less stature reduction (P=0.05; ES=1.1) and greater stature recovery (P=0.02; ES=0.9) in the afternoon compared to the morning. The chronic low back pain group experienced a similar pattern to the asymptomatic group, however no significant difference between sessions for changes in stature was evident P=0.07.
Further investigations of stature recovery should be restricted to the morning when comparing individuals with and without chronic low back pain, as time of day appeared to have effect on stature recovery, particularly in the asymptomatic group. Time dependent differences in stature change between these two populations warrants further investigation.
由设定负荷导致的无症状个体身高降低，在一天中较晚时段（即身高处于昼夜变化低谷时）幅度较小；因此，大多数身高降低研究在早晨进行。最近有证据表明，最重要的不是身高降低，而是身高恢复。本研究的目的是确定身高恢复是否也受一天中时间的影响，并确定慢性下腰痛组与无症状组之间是否存在差异。
11名慢性下腰痛参与者（年龄=32.8±7.9岁，体重=74.4±14.2千克，身高=1.73±0.07米）和11名无症状参与者（年龄=31.0±6.3岁，体重=72.6±11.5千克，身高=1.76±0.09米）进行了两项20分钟的负重行走任务（体重的10%），一项在上午（09:00），一项在下午（14:00），随后是20分钟的无负重恢复期。全程测量身高。
与上午相比，无症状组下午身高降低明显较少（P=0.05；效应量=1.1），身高恢复明显更多（P=0.02；效应量=0.9）。慢性下腰痛组的模式与无症状组相似，但身高变化在各时段之间无明显差异（P=0.07）。
在比较有和没有慢性下腰痛的个体时，进一步的身高恢复研究应限于早晨，因为一天中的时间似乎对身高恢复有影响，特别是在无症状组。这两个人群之间身高变化的时间依赖性差异值得进一步研究。
