50 free start, 2012 Olympic Trials
Courtesy of: Peter H. Bick
By Dr. G. John Mullen, PT, DPT, CSCS of Swimming Science, Center of Optimal Restoration , and Mullen Physical Therapy, Creator of Swimmer's Shoulder System, Swimming Science Research Review Swimming World correspondent

SANTA CLARA, California, June 19. PLYOMETRICS start with children doing hopscotch with their friends on the playground. (Do kids still have recess?) However, this seemingly innocuous form of exercise requires specific instruction and progression for safe utilization.

Allan Phillips discussed plyometrics more than a year ago ( Plyometrics and Swimming), but upon reviewing the literature of plyometrics and swimming, the more gaps I realized exist. Take a journey about what we know about plyometrics and swimming and then what is still unknown.

Comparable Swimming and Plyometrics
First, Cressor (1999) compared 38 adolescent swimmers (average age: 11.7 years) and split into an experimental (PG) or control (SG) group. Before and after the training, two hand-timed, push-start, maximal effort 50m swims as well as vertical jump height were performed by each swimmer.

The SG performed three times per week for 1.5 hours and the PG group swam three times a week for 1.25 hours and performed plyometric training for 30 minutes before each session. The 30 minutes of plyometric were split into a warm-up, exercise period (15-minutes), and a cool-down. The main exercise period consisted of two sets of 10 - 15 repetitions completed. This volume was chosen to be approximately the same amount of tumble turns performed in the SG. Cressor notes no significant differences between the groups after 20 weeks of training.

Both groups improved, but there were no significant differences between these intermediate adolescent swimmers.

What we know
Plyometric training volume equal to SG volume does not improve jump height or swimming parameters in intermediate level adolescent swimmers.

Plyometrics Improve Starts Compared to Nothing
Next, Bishop in 2009 took 22 trained swimmers (average age: 13.1 years; minimum of 8 hours/week; best 50m freestyle average was 35 seconds) and split them into a plyometric training (PT) or habitual training (HT) group. The PT group was given an additional two hours per week of specific plyometric exercises for eight weeks. Land and water testing was performed before and after the eight weeks. The PT group had significantly greater change in time to 5.5m, takeoff to water contact, distance to head contact, and time to head contact. No significant changes were noted in angle out of blocks and angle of entry into water. The swim time to 5.5 meters was improved on average by 0.59 seconds or 15 percent.

What we know
PT improves starting power, subsequently improving swimming velocity when compared to no additional training in intermediate adolescent swimmers.

Plyometrics Improve Swimming Performance Compared to Nothing
In 2011, Potdevin took 33 adolescent swimmers (M=10, F=13) who swam 5.5 hours/week and split them split into a control (C) or plyometric group (PG) for six weeks. The PG performed two training sessions/week and a total of 2,146 jumps were performed. The PG was systematic and progressive using a variety of double and single limb jumps. Swimming and land performance tests were performed before and after the six weeks. The PG had significant increases in the countermovement jump (CMJ) and squat jump (SJ). The PG had significant improvements in maximal glide speed. Swimming velocity during a 400- and 50-meter swim significantly increased in the PG.

What we know
Plyometric training improves power and swimming performance compared to no additional training in intermediate adolescent swimmers.

What we don't know
At the surface, it seems plyometrics provide a lot of benefit. However, several gaps in the literature exist. Here is what we don't know about plyometrics:

1. Are plyometrics more beneficial than overreaching swimming? Cressor (1999) would argue no, but the other two groups did not have the control group swim more. Giving one group another training modality (plyometrics in this scenario) appears better than nothing. But, are plyometrics truly better than simply spending the extra time swimming?

2. Is the extra time spent doing plyometrics better than other forms of dry-land? Perhaps a simple strengthening program is more appropriate for improvement. The literature is rich with controversy about the transference of resistance training and swimming performance; nonetheless, better studies are still necessary to provide the answers.

3. Are these results applicable to adults? All these studies are done in adolescents, making the results impossible to translate to older swimmers. As we age, many body changes occur, questioning the applicability of these results to older swimmers.

4. Is this applicable to elite swimmers? The swimmers in this study were intermediate, but not elite. Knowing if this works with elite swimmers is necessary as simply performing these methods in dryland may impair or improve elite swimmers. Unfortunately we don't know the answer.

Clearly, more research is necessary on the subject of plyometrics and swimming performance. However, the current state of research does not recommend or disprove the use of plyometrics for swimming performance. Nonetheless, if you are using plyometrics, having a progressive, individualized plan for each swimmer is key for health and safety.

1. Potdevin FJ, Alberty ME, Chevutschi A, Pelayo P, Sidney MC. Effects of a 6-week plyometric training program on performances in pubescent swimmers. J Strength Cond Res. 2011 Jan;25(1):80-6.
2. Bishop DC, Smith RJ, Smith MF, Rigby HE Effect of plyometric training on swimming block start performance in adolescents. J Strength Cond Res. 2009 Oct;23(7):2137-4.
3. Cossor JM, Blanksby BA, Elliott BC. The influence of plyometric training on the freestyle tumble turn. J Sci Med Sport. 1999 Jun;2(2):106-16.

Dr. G. John Mullen received his Doctorate in Physical Therapy from the University of Southern California and a Bachelor of Science of Health from Purdue University. He is the founder of the Mullen Physical Therapy, the Center of Optimal Restoration, head strength coach at Santa Clara Swim Club, creator of the Swimmer's Shoulder System, and chief editor of the Swimming Science Research Review.