研究目的：赛前热身在短距离游泳比赛中对成绩发挥有着重要作用。游泳运动员在结束一次热身后至比赛前，存在较长时间间隔的过渡期导致运动员一次热身获得的增益效果下降。因此，为了在比赛中获得更好地运动表现就需要运动员进行二次热身。本研究探索在比赛前的过渡期内，以弹力带为手段，设计50米蛙泳的赛前二次热身方案，比较不同弹力带二次热身方案实施效果，为游泳运动员和教练员提供实际可行的二次热身科学方案。

研究方法：采用随机交叉实验设计，以18名高水平游泳运动员为实验对象，分为3组，每组6人，每名受试者均要完成9次二次热身方案的测试，每次测试之间至少间隔48小时，每周至多两次测试，共五周，实验开始时每组实施不同方案的顺序随机。9次测试方案包括3次自由活动方案（N：Normal）的测试以及6次不同负重与不同恢复时间组合的干预方案，两种不同负重为中等负重（M：Moderate，60%-84%1RM）以及高等负重（H：High，＞85%1RM），三种不同恢复时间为4分钟、8分钟和12分钟。通过视频分析软件获得50米蛙泳各阶段成绩以及途中游技战术指标数据，每次测试在干预前后以及比赛前后记录受试者的心率、温度和主观用力程度指标。

研究结果：（1）与自由活动方案（N）相比较，H12方案（＞85%RM+12分钟恢复时间）、M12方案（60%-84%RM+12分钟恢复时间）、M8方案（60%-84%RM+8分钟恢复时间）以及M4（60%-84%RM+4分钟恢复时间）方案的50米蛙泳成绩、出发阶段成绩以及途中游阶段成绩显著提高（P＜0.05），H12以及M12方案的冲刺阶段成绩显著提高，且差异具有统计学意义（P＜0.05）。其中，M12方案为总成绩最快的方案。

（2）同恢复时间的两种不同负重方案之间相比较，中等负重方案的50米蛙泳成绩显著优于高等负重方案（P＜0.05）。出发阶段以及冲刺阶段成绩在同恢复时间条件下，均为中等负重方案的成绩更快，但除4分钟恢复时间的方案外（P＜0.05），其他恢复时间方案的差异不具有显著性（P＞0.05）。与高等负重方案相比，途中游阶段成绩在4分钟以及8分钟恢复时间条件下，中等负重方案的成绩均更快（P＜0.05），但在12分钟恢复时间条件下，则是高等负重方案的成绩优于中等负重方案，但差异不具有统计学意义（P＞0.05）。

（3）同负重的三种不同恢复时间方案之间相比较，12分钟恢复时间方案的50米蛙泳成绩显著优于4分钟以及8分钟恢复时间方案（P＜0.05）。出发阶段成绩在同负重条件下，中等负重方案中12分钟恢复时间的成绩最快，但三种方案之间的差异不具有显著性（P＞0.05）。高等负重方案中也是12分钟恢复时间的成绩最快，但与另外两种恢复时间方案相比差异具有显著性（P＜0.05）。途中游阶段成绩在同负重条件下，与4分钟和8分钟恢复时间的方案相比，12分钟恢复时间方案的成绩最快（P＜0.05）。冲刺阶段成绩在同负重条件下，同中等负重中，12分钟恢复时间方案的成绩优于8分钟恢复时间方案，且差异具有显著性（P＜0.05），同高等负重中，12分钟恢复时间方案的成绩显著优于4分钟恢复时间方案（P＜0.05）。

研究结论与建议：

结论：（1）6种干预方案中共有4种方案可以提高后续比赛50米蛙泳的成绩，但在不同阶段的成绩表现上4种方案略有所不同。M12（60%-84%RM+12分钟恢复时间）方案在总成绩、出发成绩以及冲刺成绩均为最快的方案，但途中游成绩H12（＞85%RM+12分钟恢复时间）方案成绩更快。（2）在同恢复时间条件下，中等负重方案的总成绩、出发成绩以及冲刺成绩更快，而高等负重方案的途中游成绩更快。（3）在同负重条件下，中等负重以及高等负重方案的总成绩以及各阶段成绩均为12分钟恢复时间方案的成绩更快。

建议：（1）在游泳比赛前，运动员可以在过渡期以弹力带作为负重的手段进行赛前二次热身。（2）赛前的弹力带二次热身建议应在正式比赛前预留12分钟左右的恢复时间。（3）对于途中游阶段能力不足的运动员可以采用高等负重方案作为赛前二次热身方案，以提高途中游阶段的成绩；对于出发和冲刺阶段能力不足的运动员可以采用中等负重方案作为赛前二次热身方案，以提高出发和冲刺阶段的成绩。

Research purposes: Pre-competition warm-ups play an important role in the performance of short-distance swimming competitions. After a swimmer finishes a warm-up and before the race, there is a long interval of transition that causes the athlete's gain from one warm-up to decrease. Therefore, a second warm-up is needed to achieve better performance in the race. This study explores the use of elastic bands as a means to design a pre-competition secondary warm-up program for the 50m breaststroke during the transition period before the competition, and compares the effects of the implementation of different elastic band secondary warm-up programs to provide swimmers and coaches with a practical and feasible secondary warm-up scientific program.

Research methods: A randomized crossover experimental design was used with 18 high-level swimmers, divided into 3 groups of 6 each. Each subject was to complete the 9 tests of the elastic band secondary warm-up protocol with a minimum interval of 48 hours between each test and up to two tests per week for five weeks, with the order of different protocols implemented in each group randomized at the beginning of the experiment.9 The test protocol consisted of three tests with a free movement protocol (N: Normal) and six intervention protocols with different combinations of weights and recovery times, two different weights for moderate (M: Moderate, 60%-84% 1RM) and high (H: High, >85% 1RM) and three different recovery times of 4, 8 and 12 minutes. Data on the performance of each phase of the 50 m breaststroke and on the technical and tactical indicators of the en route swim were obtained by video analysis software, and the subjects' heart rate, temperature and subjective exertion level indicators were recorded before and after the intervention and before and after the race in each test.

Results: (1) Compared with the free activity protocol (N), the 50 m breaststroke performance, the start phase performance and the en route swim phase performance of the H12 (>85% RM + 12 min recovery time), M12 (60%-84% RM + 12 min recovery time), M8 (60%-84% RM + 8 min recovery time) and M4 (60%-84% RM + 4 min recovery time) protocols The difference was statistically significant (P < 0.05) for the H12 and M12 regimens for the sprint phase. Among them, the M12 protocol was the fastest protocol in terms of overall performance.

(2) When comparing between the two different weighting regimens with the same recovery time, the 50 m breaststroke performance was significantly better in the medium weighting regimen than in the high weighting regimen (P < 0.05). The performance of the start phase and the sprint phase was faster for the medium-weight regimen at the same recovery time, but the difference was not significant for the recovery time regimen except for the 4-minute recovery time regimen (P < 0.05). Compared to the higher weighted scenario, the en route swim phase performance was faster in both the 4-minute and 8-minute recovery time conditions for the medium weighted scenario (P < 0.05), but in the 12-minute recovery time condition, the higher weighted scenario outperformed the medium weighted scenario, but the difference was not statistically significant (P > 0.05).

(3) Comparing between the three different recovery time regimens with the same weight, the 50 m breaststroke performance was significantly better in the 12-minute recovery time regimen than in the 4-minute as well as the 8-minute recovery time regimens (P < 0.05). In the departure phase, the 12-minute recovery time was the fastest in the medium-weight scenario under the same weight conditions, but the difference between the three scenarios was not significant (P > 0.05). The 12-minute recovery time was also the fastest in the high-weight scenario, but the difference was significant compared to the other two recovery time scenarios (P < 0.05). The en route swim phase performance was the fastest in the 12-minute recovery time scenario compared to the 4- and 8-minute recovery time scenarios under the same weight conditions (P < 0.05). The performance of the sprint phase was better in the same weight conditions, with a significant difference (P < 0.05) in the 12-minute recovery time scheme than in the 8-minute recovery time scheme in the same medium weight, and in the same high weight, the 12-minute recovery time scheme was significantly better than the 4-minute recovery time scheme (P < 0.05).

Conclusion and recommendations: Conclusion: (1) The M12 (60%-84% RM + 12 min recovery time) scenario was the fastest in total, start and sprint times, but the H12 (>85% RM + 12 min recovery time) scenario was faster in the en route. (2) Under the same recovery time conditions, the overall, start and sprint times were faster for the medium-weight scenario, while the en route swim times were faster for the higher-weight scenario. (3) Under the same weight conditions, the overall performance as well as the performance in each phase were faster for the medium-weight as well as the higher-weight protocols for the 12-minute recovery time protocol.

Recommendations: (1) Before the swim meet, athletes can use the elastic band as a means of weight-bearing during the transition period for the pre-competition secondary warm-up. (2) The pre-race secondary warm-up with elastic bands is recommended to allow about 12 minutes of recovery time before the official race. (3) For athletes with insufficient ability in the en route stage, a high weight-bearing program can be used as the pre-race secondary warm-up program to improve the performance in the en route stage; for athletes with insufficient ability in the start and sprint stages, a medium weight-bearing program can be used as the pre-race secondary warm-up program to improve the performance in the start and sprint stages.