PURPOSE This study compared the spatiotemporal gait parameters and kinetic variables of lower extremity joints during gait between normal and presarcopenia groups of middle-aged women. METHODS Middle-aged women participants (n=24) were divided into two groups based on the Appendicular Lean Mass Index (ALMI): a normal group (n=12) and a presarcopenia group (n=12). During walking by each group, spatio-temporal gait variables and the maximum moments and net joint power of the ankle, knee, and hip joints in different directions were calculated and compared using independent samples t-tests with IBM SPSS 27.0 software. RESULTS The normal group and the presarcopenia group showed no statistically significant differences in spatiotemporal gait variables. However, during the shock absorption phase of gait, the presarcopenia group showed significantly higher maximum knee abduction, maximum knee internal rotation, and maximum hip external rotation moments than the normal group. Additionally, the presarcopenia group exhibited significantly higher maximum net knee power during the shock absorption phase. Conversely, during the propulsion phase of gait, the normal group exhibited significantly higher maximum net ankle power than the presarcopenia group. CONCLUSIONS Middle-aged women with presarcopenia experienced higher knee joint loading and lower ankle joint propulsion during walking, indicating the need for training to improve lower limb strength.
PURPOSE This study analyzed the effect of dynamic lumbar kyphosis on the biomechnical factors affecting the lumbar joints during deep squats. METHODS Thirty adults in their 20s who had experienced weight training for more than one year participated in this study (age: 23.4±3.5years old, height: 175.3±4.3cm, weight: 75.8±6.5kg, squat single repetition maximum (1RM) weight: 115.3±19.5kg). Under both restricted dynamic lumbar kyphosis (RDLK) and dynamic lumbar kyphosis (DLK), subjects completed one repetition of deep squats at a load of 70% of their 1-RM weight. To verify the consistency of deep squat movements performed under DLK and RDLK conditions, intra-rater reliability was analyzed using intra-class correlation . The biomechnical variables of the lumbar joint were calculated during DLK and RDLK deep squats. Paired sample t-tests (IBM SPSS 27.0, Armonk, New York, USA) were used for statistical verification. RESULTS During the deep squat movement performed in DLK and RDLK conditions, the peak angles of the ankle, knee, and hip joints, the minimum height of the pelvis, and the time and tempo showed statistically high reliability, confirming the accuracy of the movement. The peak flexion angle and moment, left flexion moment, left rotation moment, and compression force factors of the lumbar joint during deep squat were significantly lower in RDLK than in DLK. CONCLUSIONS Restricting lumbar dynamic kyphosis during deep squats is essential for decreasing the risk of lumbar joint injury.
