The purpose of this study is to investigate the impact of walking at different speeds with wearing unstable shoes on the movement of the lower limbs, and to provide relevant biomechanical supports for fitness and injury prevention. Methods: Twelve females volunteered to join the test. The walking speed was respectively 0.80 m/s, 1.20 m/s and 1.70 m/s. The kinematic parameters of the lower limb of ankle, knee and hip measured with Vicon motion analysis system. And univariate repeated measurements of variance analysis was used to measure the effect of unstable shoes in lower limbs joints in three differences speeds. Results: The movement pattern of the hip joint is relatively stable and is less affected by the speed. It is mainly manifested in the extension, abduction and external rotation of the hip joint. The knee joint is affected by the walking speed, especially in the coronal plane and the horizontal plane. The angle range of motion of the ankle joint are larger than hip joint, there have increased of the dorsiflexion, inversion and internal rotation in ankle joint. Conclusion: For the lower extremities of the hip, knee and ankle joints, with the increase of walking speed, joint angle and range of activities also showed varying degrees of increase; and joint angle peaks are in the pre-support period.

Purpose: This study investigated the changes in the blood indices, specific athletic abilities, and physical fitness of outstanding cross-country skiers, trained in the subalpine; Methods: Twenty-eight athletes (twenty males and eight females) from the National Cross-country Ski Training Team completed sub-alpine training during the 2020–2021 snow season. The athletes′ physical functions were evaluated by collecting blood from elbow veins and measuring blood biochemical indexes. To compare the treadmill roller-skiing athletic ability and physical fitness of athletes before and after subalpine; Results: Male and female athletes showed different trends in red blood cells (RBC), hemoglobin (Hb), cortisol (C), Creatine Kinase (CK) and blood urea (BU) (p < 0.05 or p < 0.01). Overall, the female athletes’ mean values of RBC, Hb, CK, and BU were lower than that of male athletes, while C was just the opposite. Comparing the athletic performance of athletes before and after the subalpine, it was found that blood lactate concentrations were significantly lower in both male and female athletes at the same load intensity (p < 0.05 or p < 0.01), whereas 10 km endurance running and 1 RM deep squat were significantly higher in both male and female athletes (p < 0.05 or p < 0.01). Conclusions: After 6 months of subalpine training, cross-country skiers improved their oxygen-carrying capacity and anabolism, and showed significant improvements in specific athletic ability, physical endurance, acid tolerance and 1 RM absolute strength for both male and female athletes.

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