Abstract：
During forward flexion, spine motion varies due to age and sex differences. Previous studies showed that lumbar/pelvis range of flexion (RoF) and lumbo-pelvic ratio (L/P) are age/sex dependent. How variation of these parameters affects lumbar loading in a normal population requires further assessment. We aimed to estimate lumbar loads during dynamic flexion-return cycle and the differences in peak loads (compression) and corresponding trunk inclinations due to variation in lumbar/pelvis RoF and L/P. Based on in vivo L/P (0.11-3.44), temporal phases of flexion (early, middle, and later), the lumbar (45-55°) and hip (60-79°) RoF; full flexion-return cycles of six seconds were reconstructed for three age groups (20-35, 36-50 and 50+ yrs.) in both sexes. Six inverse dynamic analyses were performed with a 50th percentile model, and differences in peak loads and corresponding trunk inclinations were calculated. Peak loads at L4-L5 were 179 N higher in younger males versus females, but 228 N and 210 N lower in middle-aged and older males, respectively, compared to females. Females exhibited higher trunk inclinations (6°-20°) than males across all age groups. Age related differences in L4-L5 peak loads and corresponding trunk inclinations were found up to 415 N and 19° in males and 152 N and 13° in females. With aging, peak loads were reduced in males but were found non-monotonic in females, whereas trunk inclinations at peak loads were reduced in both sexes from young to middle/old age groups. In conclusion, lumbar loading and corresponding trunk inclinations varied notably due to age/sex differences. Such data may help distinguishing normal or pathological condition of the lumbar spine.
摘要：
在前屈时,脊柱运动因年龄和性别差异而不同。先前的研究表明，腰椎/骨盆屈曲范围（RoF）和腰骨盆比（L/P）与年龄/性别有关。这些参数的变化如何影响正常人群的腰椎负荷需要进一步评估。我们旨在估算动态屈曲-返回循环期间的腰椎载荷，以及由于腰椎/骨盆RoF和L/P的变化而导致的峰值载荷（压缩）和相应躯干倾斜度的差异。基于体内L/P（0.11-3.44），屈曲的时间阶段(早期，中间,稍后)，腰椎（45-55°）和髋部（60-79°）RoF；对三个年龄组（20-35、36-50和50岁以上）重建了6秒的完整屈曲-返回周期。)两性。用第50百分位数模型进行了6次逆动态分析，并计算了峰值载荷和相应的树干倾角的差异。L4-L5的峰值负荷在年轻男性比女性高179N，但在中年和老年男性中，228N和210N较低，分别,与女性相比。在所有年龄段中，女性的躯干倾斜度（6°-20°）均高于男性。在男性中发现L4-L5峰值负荷和相应的躯干倾角的年龄相关差异高达415N和19°，在女性中发现152N和13°。随着年龄的增长，峰值负荷在男性中降低，但在女性中发现非单调，而从青年到中年/老年组，男女在峰值负荷时的躯干倾斜度均降低。总之,由于年龄/性别差异，腰椎负荷和相应的躯干倾斜度显着变化。这些数据可以帮助区分腰椎的正常或病理状况。
