A Study on the Effects and Mechanisms of Plyometric Training on Lower Limb Muscle Strength and Agility of College Students in Vocational Colleges

Objective: To explore the improvement effects of plyometric training on lower limb muscle strength and agility of college students in vocational colleges, analyze the internal physiological mechanism and the synergistic correlation between the two, construct a standardized plyometric training scheme suitable for this specific group, and provide high-quality empirical evidence and practical guidance for the targeted development of lower limb physical training in vocational colleges. Methods: Sixty freshmen male students without systematic physical training foundation and no history of sports injury from the School of Computer Science, Guangdong Vocational and Technical University of Business and Technology were selected as research subjects, and divided into an intervention group (30 people) and a control group (30 people) by random number table method. The intervention group received 16 weeks of lower limb special plyometric training (twice a week, 30-40 minutes each time), and the control group received conventional physical training with the same frequency and duration. Results: (1) After training, all indicators of lower limb muscle strength in both groups were significantly improved compared with those before training (P<0.01), but the improvement range of the intervention group was significantly higher than that of the control group (P<0.05). The improvement rates of 1RM squat, vertical jump height and squat jump power in the intervention group were 28.45%, 22.17% and 25.32% respectively, while those in the control group were 10.36%, 6.78% and 8.92% respectively. (2) After training, the completion time of all lower limb agility indicators in both groups was significantly shortened compared with that before training (P<0.01), and the optimization effect of the intervention group was significantly better than that of the control group (P<0.05). The shortening rates of 5-10-5 agility run, T-run and hexagon jump in the intervention group were 14.23%, 13.56% and 15.78% respectively, while those in the control group were 4.12%, 3.89% and 4.35% respectively. (3) After training, the RMS values of electromyographic signals of quadriceps femoris and gastrocnemius in both groups were significantly increased compared with those before training (P<0.01), and the improvement rates of the intervention group (48.65%, 49.32%) were significantly higher than those of the control group (19.45%, 21.18%) (P<0.05). (4) Pearson correlation analysis showed that the change values of neuromuscular activation indicators in the intervention group were significantly positively correlated with the change values of lower limb muscle strength and agility indicators (r=0.582-0.713, P<0.01); the improvement values of lower limb muscle explosive power (vertical jump height, squat jump power) were significantly positively correlated with the improvement values of agility indicators (r=0.654-0.731, P<0.01). Conclusion: Plyometric training can significantly improve the lower limb muscle strength and agility of college students in vocational colleges, and the effect is better than conventional physical training; its core mechanism is closely related to the improvement of neuromuscular activation efficiency and the enhancement of skeletal muscle stretch reflex function; the improvement of lower limb muscle explosive power is an important support for agility optimization, and there is a synergistic improvement effect between the two. The training scheme constructed in this study is suitable for the physiological characteristics of this group and campus training scenarios, and can be directly applied to physical education teaching and after-school physical training in this university, providing scientific support for the precise optimization of lower limb physical training for college students of specific majors in vocational colleges, and also providing a reference paradigm for similar studies.