Strength Training on Muscle Power Output and Neuromuscular Adaptation Among China University Long Jump Athletes

The purpose of this study is to investigate the effects of optimal load strength training on the lower limb neuromuscular adaptation of athletes. An anatomical analysis of the vertical jump reveals three phases: the propulsion phase, the flight phase, and the landing phase.

This study is an 8-week randomized controlled trial. After selecting the participants, basic information such as height, weight, age, and years of training experience is collected. Subsequently, a maximal output power test for lower limb squatting is conducted. Participants are then randomly assigned to the speed group, power group, and strength group. The optimal power load for the power group is determined based on the participant maximal output power. Training plans are developed for the traditional group, power group, and strength group. Each training session is organized and supervised by a designated person. Surface electromyography, three-dimensional motion capture systems, and force platforms are used to collect electromyographic and kinetic data of participants during pre-test and post-test vertical jump actions. Electromyography evoked potential instruments and myotonometer are used to collect nerve signals of the tibial nerve (posterior calf) and muscle fiber dimension data of the rectus femoris before and after the experiment. Additionally, static full-range-of-motion vertical jump kinematics and kinetics data are collected before and after the experiment. To ensure the quality and validity of the intervention, the following controls are implemented during the experiment: first, communication with the participants to inform them of the purpose of the study and ensure adherence to the correct movement standards during testing; second, having a designated person responsible for resistance training during the experiment; third, using the same equipment and team for testing to maximize the controllability of the experiment process; fourth, providing verbal encouragement to participants during testing to maximize effort and minimize experimental errors. The aim is to determine the effects of optimal load strength training on improving the lower limb output power during the propulsion phase of the take-off stage in long jump athletes and the underlying neuromuscular adaptation mechanisms.

In this study, the experimental group conducted 8 weeks of maximum output power strength training, and the control group also conducted 8 weeks of explosive power training (strength combined with speed). The subjects trained twice a week, and each training was not based on time, but on the number of times multiplied by the number of groups. The training load in the 8-week strength training of the experimental group was the load weight corresponding to the maximum output power of the subjects, and the training load in the control group was between 70% and 85% of the maximum strength. In the control group, the entire cycle was divided into three stages, 1-2 weeks: Adaptation period; 3-5 weeks: Enhancement period; 6-8 weeks: Stabilization period; the experimental group had no period division. The equipment for strength training in both the experimental and control groups was the Smith rack. The experimental group used weighted half squat jumps, and the control group used weighted half squat jumps plus knee hug jumps.

Eligibility Criteria:
Inclusion Criteria:

1. Aim for uniformity in various indicators to minimize errors caused by height, weight, and training experience differences.
2. Aim for a 1RM/body weight ratio of around 2.
3. Maintain normal diet and sleep patterns during the training period, and refrain from using supplements such as creatine and protein powder.
4. Male university long jump athletes should be aged ≥18, and they should not have engaged in strength training 48 hours before the baseline testing.

Exclusion Criteria:

1. Participants with various visceral diseases and abnormal liver or kidney function are excluded.
2. Those with unhealthy habits are excluded.
3. Participants with caffeine intake within 3 hours before testing are excluded.
4. Individuals who have engaged in high-intensity resistance exercises within the past 24 hours are excluded.
5. Those with lower limb joint injuries (open and closed) in the last 3 months are excluded.
6. Participants with contraindications such as cardiovascular diseases, skin allergies, and hernia are excluded.