Background and Purpose
In competitive swimming, especially in sprint swimming, a strong start is crucial for achieving better records and requires increasing the explosive power of swimmers. Factors such as reaction time, high jump power and reduced underwater resistance are essential for an effective start, which can be improved with appropriate training. Plyometric training, by enhancing the stretch-shortening cycle (SSC), helps to increase muscle power, especially in the lower and upper limbs, and improves swimming performance over various distances. By creating rapid explosive movements, these exercises are very effective for sports such as swimming that require speed and power. Studies have shown that plyometric training in water and on land improves start times and breaststroke records and increases anaerobic power. For example, research has shown that six to eight weeks of plyometric training significantly improves swimmers' performance over distances of 10 to 25 meters. These exercises are particularly beneficial for adolescent swimmers, promoting improvements in strength, speed, and agility at an early age, which continue into adulthood. Coaches often focus on the upper body, while the lower body has greater potential for power generation. Comparing plyometric training in water and on land helps optimize training programs and provides a better understanding of the advantages and disadvantages of each environment. This will help coaches and swimmers design more effective programs. Finally, the present study examined the effect of eight weeks of plyometric training in water and on land on anaerobic power and swimming record in adolescent boys to provide insights for improving training methods and developing elite swimmers.
Materials and Methods
The research population consisted of 30 male art students aged 9 to 15 years from the city of Lasht-e-Nesha, Rasht, who were selected from 45 volunteers with the inclusion criteria (no cardiovascular disease, no sports injury, and regular training for at least 6 months). After being called by the swimming committee and coordinating with their parents, the subjects were transferred to the exercise physiology laboratory of the University of Guilan and their anthropometric indices (height, weight, BMI, waist-to-hip ratio) were evaluated. Then, they were randomly divided into two groups of 15 (plyometric exercises in water and on land). After 10-15 minutes of general and specific warm-up, each group performed plyometric exercises, including 12 jumping movements (such as high knee jumps, squats, and deep jumps), three sessions per week for 8 weeks. Upper body anaerobic power was measured with a Monarch hand-held ergometer (resistance 5.5% of body weight) and lower body with a Monarch bicycle (resistance 7.5% of body weight) in a 30-second Wingate test. The 33-meter swimming record was recorded with a stopwatch and by 5 judges. The subjects' diet was monitored and a food questionnaire was completed. The post-test was performed 48 hours after the last training session. The data were analyzed using descriptive (mean, standard deviation) and inferential statistics (two-way analysis of variance and Bonferroni test) in SPSS version 24 software.
Results
The results of the study showed that plyometric training in water and on land significantly improved the 33-meter swimming record of adolescent swimmers (p<0.05), with a decrease of 5.02% in the water group and 4.02% in the land group, indicating the relative superiority of water training (F=4.18, p=0.042). Peak lower body power improved significantly in both groups (water: p=0.002, land: p=0.034), with the water group being superior in the post-test (p=0.039) and the percentage of changes was 14.63% (water) and 9.04% (land). The mean lower body power also improved in both groups (water: p=0.039, dry: p=0.004), but the dry group had a relative advantage in the post-test (p=0.045) with changes of 13.04% (dry) and 12% (water). Peak upper body power significantly improved in both groups (water: p=0.034, dry: p=0.001) with changes of 18.67% (dry) and 15.47% (water), but the difference between the groups was not significant in the post-test (p=0.061). The mean upper body power also improved (water: p=0.003, dry: p=0.040) with changes of 14.91% (dry) and 13.77% (water), without a significant difference between the groups (p=0.058). The upper body fatigue index decreased in both groups (water: p=0.048, dry: p=0.033) with changes of -1.93% (water) and -2.12% (dry), with no significant difference between groups (p=0.065). The lower body fatigue index also decreased significantly (water: p=0.031, dry: p=0.045) with changes of -9.21% (water) and -17.80% (dry) and a significant difference between groups at post-test (p=0.023). In general, plyometric training in water was more effective for swimming record and peak lower body power, while training on land was relatively superior for average lower body power and peak upper body power.
Conclusion
The results of the study showed that eight weeks of plyometric training in water and on land significantly improved the 33-meter swimming performance of adolescent swimmers, which is consistent with the findings of Arazi et al. (2011), Rajman et al. (2017), Orta et al. (2023), Adigozel et al. (2016), and Lavant et al. (2017). These exercises increase explosive power and speed by strengthening the stretch-shortening cycle (SSC), muscle strength, and neuromuscular coordination, especially in jumping movements such as diving. Peak and average lower body power improved in both groups, but the water group had a relative advantage (14.63% vs. 9.04% for peak power). Plyometric training enhances explosive force generation capacity by stimulating muscle spindles and storing elastic energy. Unlike the study by Kasser et al., which reported no effect of plyometric training, the difference in training duration (short-term in this study) is likely the reason for the discrepancy. Also, diving training with auditory stimuli reduced reaction time (13±9 ms after four weeks). Elite swimmers had shorter block times than adolescents, but no significant difference in reaction time was observed. Plyometric training improves peak and average power due to the use of SSC and increased neural efficiency, which is critical for sports such as swimming, soccer, and basketball. The aquatic environment improves performance by reducing stress on the musculoskeletal system and increasing resistance. Although upper body anaerobic power did not differ significantly between the two groups, training in water was more effective for lower body power. Limitations of the study include the small sample size and the lack of complete control of confounding factors. Coaches can use water or land training as needed.
Article Message
Eight weeks of plyometric training conducted both in aquatic and land environments significantly improved sprint performance and anaerobic power in adolescent swimmers. These findings suggest that coaches may utilize either aquatic or land-based plyometric training, depending on available facilities and training objectives, to effectively enhance the athletic performance of adolescent swimmers.
Ethical Considerations
This study was approved by the Guilan Research Ethics Committee in Biomedical Research, in accordance with the guidelines of the Declaration of Helsinki.
Authors’ Contributions
Conceptualization: (Payam Saidie, Ghader Ahmadzadeh)
Data Collection: (Ghader Ahmadzadeh.)
Data Analysis: (Ghader Ahmadzadeh, Payam Saidie.)
Manuscript Writing: (Ghader Ahmadzadeh, Payam Saidie, Abuzar Jorbonian, Ashkan Golabi.)
Review and Editing: (Payam Saidie, Abuzar Jorbonian, Ashkan Golabi)
Responsible for funding: (Ghader Ahmadzadeh)
Literature Review: (Ghader Ahmadzadeh, Payam Saidie, Abuzar Jorbonian, Ashkan Golabi)
Project Manager: (Payam Saidie, Abuzar Jorbonian)
Conflict of Interest
According to the authors, this article has no conflict of interest.
Acknowledgments
We sincerely thank and appreciate all the subjects who contributed to this study with their valuable cooperation and participation.