Photo Courtesy: David Farr
Commentary by G. John Mullen
SANTA CLARA, California, September 17. IN my last post, I reviewed some information regarding dryland training. Overall, dryland/strength training is a poorly research field, leaving many gaps in the literature. However, reviewing the complete body of literature, using the highest quality of research, and not lumping all dryland together is essential for evaluation and recommendation. Here is a review of more studies on strength training and swimming which I can find. Unfortunately, in every literature review, finding each article on the subject is impossible. If any readers have research articles, please post them in the comments:
Strass (1986) found a 7.3% improvement in 50m freestyle with the intervention group after a heavy, explosive strength training regimen (three repetitions per three sets at 90% resistance of one-repetition maximum (1RM), two repetitions per two sets at 95% of 1RM, one repetition at 100% of 1RM and one repetition attempted at 100% of 1RM+1kg) of the elbow extensors for four sessions per week across 6 weeks.
Like other studies mentioned, this study had some flaws. Strass (1986) did not supply any control group data from pre- or post-tests in numbers. He did, however, report a small, but possibly significant age difference between the groups (mean age 16.6 years in the intervention group and mean age 17.8 years in the control group, not reporting whether the difference was significant). Furthermore, the measurements of isometric force may limit the data interpretation, as swimming is a dynamic exercise and isometric tests may not always be an accurate measure of dynamic muscular capacity (Wilson 1996).
Overall, this high-intensity low volume (only one exercise!) resistance training approach may improve 50-m performance.
Girold (2007) compared strength training (S), resisted swimming (RS), and a control group (C; biking). This trial was 12-weeks and the training was performed biweekly. The resistance training specifically was explosive dryland strength training (six different exercises with three times six repetitions of explosive-type strength training at 80–90% of 1RM).
Improvements in strength training were supported by Girold (2007) finding improvement in the 50m freestyle after 12 weeks of biweekly sessions of This trial compared strength training (S), resisted swimming (RS), and a control group (C; biking). The strength and resisted swimming groups had significant improvement in a 50-meter time trial. The strength group improved 2.8%, resisted swimming 2.3% and control 0.9%. There was no significant difference between the improvement of S and RS. Isometric strength of the elbow flexors was significantly increased in S and RS, but not C.
Now, this study appears positive for resistance training, but the swimmers were intermediate in speed, and the type of control training may have inhibited performance (causing overtraining). Moreover, only a 50-m was assessed, making gross assumptions of other events and distances unwarranted.
Both studies also found improvements within the respective strength parameters, and concluded that their strength-training interventions were successful. However, data from small study groups are scientifically fragile compared with larger study groups, and like many of the other studies included in this review the findings of these studies may be limited by the low number of subjects (on average 4.5 and 7).
Girold (2012) more recently looked at twenty-four national-level competitive swimmers (M=12, F=12; ~21.8 years; 27.8 +- 1.8 seconds top 50 m time) who averaged 20 hours of swim training per week. These swimmers were split into dryland (S), electrical stimulation (ES), and control (C) groups. The strength sessions were 15 minutes long, preceded by a 10-minute warm-up which was performed 3 times per week before swimming. The program included 3 sets of 3 exercises with 2 minutes rest between each set. Each set consisted of a maximum of 6 repetitions of pull-ups and draws with pulleys. “The exercises included pull-ups and draws with pulleys. To perform the exercises under the most specific conditions, they were performed with the hand in a pronation grip and the distance between the 2 hands set at shoulder width. The swimmers were instructed to pull on the bar until it reached the level of the chest when performing pull-ups and first draw exercises. For the second draw exercise, swimmers were instructed to pull on the handle until it reached the level of the hips. For pull-ups, the swimmers’ own body weight was used as resistance. For the draw exercises, the swimmers were seated on a bench with their legs locked under a bar to avoid any movement of the lower limbs. The intensity of the training varied between 80 and 90% of the maximal load for the draw exercises in relation to the 1RM tests performed before the start of the study. For each repetition, the swimmers were instructed to perform the concentric phase of the movement as fast as possible, maintain a 3-second isometric contraction and return to the initial position by slowing the movement (eccentric phase). The exercise rate was approximately 1 movement every 6 seconds (Girold 2012).”
The ES program performed the same 10-minute warm-up as the S group followed by electrical stimulation to the latissimi dorsi.
Swimming velocity significantly improved in the 50-m freestyle at the end of training in the S and ES group (2.0% and 1.7% improvement, respectively). Even four weeks after the study, significant improvement existed, but the results were not significant from one another. After 4 weeks stroke length was significantly increased in the S, but not the ES or C group. Peak torque significantly increased at moderate and fast speeds for the S and ES group. ES also improved in strength for isometric and eccentric contractions. No differences were noted between men and women.
Again, these results seem quite positive for resistance training, but keep in mind; it only looked at a 50-m velocity, no longer distances. Moreover, the volume of resistance training was quite low. Also, the training only lasted 4 weeks, with most of the improvements persisting after four weeks. This suggests, cycling through resistance training may be beneficial. For ES, it is likely this low volume may have increased strength, causing performance improvements, more studies on ES is needed.
Aspenes (2009) compared combined intervention of strength (~two weekly sessions of an explosive pull-down strength training regimen of five repetitions with maximal load relative to the number of repetitions over three sets) and endurance training (two weekly sessions of 4 times 4 minutes of high-intensity interval training), with a control group that only performed regular swimming training. The intervention was eleven weeks in total. Mean age in the intervention group was 17.5 years (n = 11, 6 males), and in the control group 15.9 years (n = 9, 2 males).
The intervention group improved land strength, tethered swimming force and 400m freestyle performance more than the control group.
Although (Aspenes 2009) partly agrees with the aforementioned trials, indicating that dryland strength training may benefit swimming performance, a crossover effect from the endurance intervention may potentially have influenced the findings (Aspenes 2009). Aspenes (2009) may also be limited by the lack of a randomization design, like many other studies. In addition, the intervention group and the control group were not similar with respect to sex (7 of 9 subjects were female in the control group, 5 of 11 subjects were female in the intervention group).
Although the previous studies are positive, opposing work does exist.
A study from Trappe and Pearson (1994) compared weight-assisted training (three sets of dips and pull-ups with no assistance until volitional fatigue, 13.6 kg assistance and 22.7 kg assistance, respectively) to dryland strength training (six exercises with three sets of 8–12 repetitions with progressive maximal load until exhaustion) in addition to common swim practice, and found no differences in 50 yard or 400 yard swimming performance between the groups.
The possible effects were inadequately controlled, as the strength training intervention was carried out during the first 6 weeks of a 12-week observation, and performance tested in weeks 4 and 12 in both groups, which makes it challenging to draw inferences. Nonetheless, the results suggest higher volume dryland is not beneficial for swimming sprints or endurance events.
Sadowski (2012) randomly assigned twenty six male swimmers (mean age 14) to either a swimming or dryland power training (experimental) or swimming only (control) group. Then the subjects were tested with hydroisokinetic ergometer. The swimming training consisted of six weeks of doubles every day except Sunday and one training session on Saturday. All subjects swam 273.50 km during the whole experiment. The power training consisted of circuit training, of 6 sets of 50 seconds of work and 10 seconds of rest on the ergometer (Sadowski 2012). The experimental group had significant improvements in tethered swimming force, but both groups noted non-statistically differences in 25-m performance.
These results suggest the common circuit training may not be beneficial for age-group swimmers for enhancing sprint swimming performance.
The reviewed studies of dryland strength training on swimming performance indicate that there may be positive associations between maximal dryland strength training and swimming performance. However, due to a low number of eligible studies, lack of information, variety between the interventions, subject characteristics and effects, low numbers of study participants, combined intervention design and lack of randomized study designs, further randomized controlled trials (RCTs) on the effects of dryland strength training should be carried out in competitive swimmers.
If any conclusions can be drawn it is the following:
1. High volume dry-land training combined with high-volume swimming unlikely enhancements performance.
2. High-intensity, low volume, short duration dryland training has the highest potential of improving sprint and endurance swimming performance.
3. There is a lack of research on this area, despite the common implementation of dryland.
The next installment will talk about other possible avenues for dryland training, as strength training is only one component. More on dryland, strength training, and team programming is available in Dryland for Swimmers.
- Girold S, Maurin D, Dugué B, Chatard JC, Millet G. Effects of dry-land vs. resisted- and assisted-sprint exercises on swimming sprint performances. J Strength Cond Res. 2007 May;21(2):599-605
- Girold S, Jalab C, Bernard O, Carette P, Kemoun G, Dugué B. Dry-land strength training vs. electrical stimulation in sprint swimming performance. J Strength Cond Res. 2012 Feb;26(2):497-505.
- Aspenes S, Kjendlie PL, Hoff J, et al. Combined strength and endurance training in competitive swimmers. J Sports Sci Med 2009 Sept; 8 (3): 357-65.
- Trappe S, Pearson D. Effects of weight assisted dry-land strength training on swimming performance. J Strength Cond Res 1994 Nov; 8 (4): 209-13.
- Strass D. Effects of maximal strength training on sprint performance of competitive swimmers. In: Ungerechts BE, Wilke K, Reischle K, editors. Vth International Symposium of Biomechanics and Medicine in Swimming; 1986 Jul 27-31. Bielefeld: Human Kinetics Books, 1986: 149-56
- Sadowski J, Mastalerz A, Gromisz W, NiŸnikowski T. Effectiveness of the power dry-land training programmes in youth swimmers. J Hum Kinet. 2012 May;32:77-86. doi: 10.2478/v10078-012-0025-5. Epub 2012 May 30.