Benefits persist 3 weeks after training
By Katie Bell
Bilateral practice should be established early in youth long-jump training programs to improve the jumping performance of their dominant (takeoff) leg, according to research from Karlsruhe, Germany, that may have implications for other track and field events.
“Even though the exact integration of training with the nondominant body side [order, frequency, etc] is not clarified yet, bilateral training per se seems to be relevant,” said first author Anne Focke, PhD, deputy director of the BioMotion Center at the Institute of Sports and Sports Science at Karlsruhe Institute of Technology.
The study included 61 athletes aged 6.75 to 13.5 years (mean ± SD: 9.66 ± 1.95 years). The athletes had 3.6 years of track and field training on average and had mastered the long jump’s main features. Investigators used jumping distance in a pretest to determine the participants’ dominant leg.
Investigators placed participants into two groups: a unilateral practice group that practiced the long jump using only the dominant leg for takeoff (n = 31, 16 girls) and a bilateral practice group (n = 30, 16 girls) that used both the dominant and nondominant legs alternately for takeoff. Both groups underwent 12 weeks of 1.5-hour, twice-weekly practice sessions that consisted of a specific long-jump practice and bilateral exercises for coordination, stabilization, and sprinting.
The unilateral and bilateral groups completed the same practice workload and did the same coordination, stabilization, and sprinting exercises.
In addition to the pretest, participants completed a post-test after the 12-week practice period and a retention test after three weeks without practice. Each test consisted of six long jumps, three using each leg for takeoff in a randomized order. Investigators analyzed the best jump of the three in terms of distance.
All participants improved their jumping performance from pre- to post-test and from post-test to retention test. The results also suggested a superior effect on the dominant leg’s jumping performance for bilateral practice compared with unilateral practice. The performance increase from pretest was significantly higher for the bilateral practice group’s dominant limb at both post-test (5.2%) and retention test (7.4%) compared with 3.4% and 4.5%, respectively, for the unilateral practice group.
“Bilateral training for unilaterally performed sports like the long jump should become normal practice.”
— Anne Focke, PhD
The jumping performance of the dominant leg from post-test to retention test also increased more in the bilateral training group than the unilateral group, but to a lesser degree in both groups compared with the change in performance from pre- to post-test. Performance of the nondominant leg was significantly higher from pre- to post-test and post-test to retention test in the bilateral training group, but not in the unilateral training group.
Bilateral training for unilaterally performed sports like the long jump should become normal practice, Focke said.
“Practice of the nondominant side improves the performance of the dominant side and so is useful during an injury-break or to avoid overtraining. Sadly, I would assume that bilateral training is only in rare cases an inherent part of the training, and is dependent on the individual sport, division, and coach,” she said.
She also noted that bilateral practice can produce a transfer of learning that can prevent an increase of lateral asymmetries, as well as improve performance of the dominant takeoff leg as well as the nondominant leg.
The European Journal of Sport Science epublished the findings in February.
Commenting on the study, Brian Mackenzie, BA(Hons), a Level 4 Performance Coach (Sprints & Combined Events) and coach tutor/assessor in Birmingham for British Athletics, the UK’s National governing body for track and field athletics, agreed with the authors’ conclusion that bilateral practice should be established early in long jump training to improve the performance of the athlete’s dominant leg.
Mackenzie added, “For maximum muscle force development, use bilateral training. When maximum force is not a priority, unilateral exercises can work well to correct asymmetry.”
Discussing exercises that are specific to jumping practice in youths and adolescents, Mackenzie said, “As their joints and tendons have not fully formed, I focus on the general skill of jumping for height [high jump] and distance [long jump] with learning to jump with left- and right-foot takeoff–the focus is more with technique in the run up, takeoff, flight, and landing phases.”
Katie Bell is a freelance writer based in New York City.
Focke A, Spancken S, Stockinger C, et al. Bilateral practice improves dominant leg performance in long jump. Eur J Sport Sci 2016 Feb 10;1-7. [Epub ahead of print]