Research article - (2026)25, 656 - 664
DOI:
https://doi.org/10.52082/jssm.2026.656
Dominant Leg Continuous Unilateral Hopping Impairs Contralateral Leg But Not Upper Body Explosive Performance
Mahta Sardroodian, Hiwa Rahmani, David G. Behm
School of Human Kinetics and Recreation, Memorial University of Newfoundland, St. John’s Newfoundland and Labrador, Canada

David G. Behm
✉School of Human Kinetics and Recreation, Memorial University of Newfoundland, St. John’s Newfoundland and Labrador, Canada
Email: dbehm@mun.ca
Received: 20-03-2026 -- Accepted: 03-07-2026
Published (online): 01-09-2026
Narrated in English

ABSTRACT

Many non-local muscle fatigue studies utilize continuous isometric contractions to induce unilateral fatigue and assess contralateral limb strength and endurance. The present study aimed to investigate the effects of dynamic unilateral lower-limb fatigue on contralateral lower-limb and upper-body explosive performance. Eighteen healthy adults (30.3 ± 9.3 years) completed sessions involving continuous exercise performed to induce fatigue (1 min of unilateral hopping), intermittent exercise performed to induce fatigue (two 30-s bouts of unilateral hopping), and a non-active control. Explosive performance was measured before the intervention and at 1, 5, and 10 min post-intervention using repeated single-leg hops (10 repetitions) and rebound push-ups (5 repetitions). Significant interactions showed that contralateral hop height (p = 0.048), reactive strength index (p = 0.003), and lower-limb power (p < 0.001) were significantly reduced 1 min post-exercise after unilateral continuous hopping. Hop height and power remained significantly lower at 5 min post-exercise (p = 0.03 and p = 0.008, respectively). In contrast, intermittent hopping did not induce significant contralateral lower-limb impairments but resulted in higher upper-body ratings of perceived exertion 1 min post-exercise compared with pre-exercise (p = 0.017) and 5 min post-exercise (p = 0.008). In conclusion, continuous unilateral hopping transiently impairs contralateral lower-limb explosive performance, whereas upper-body explosive performance remained unaffected. Intermittent hopping increases upper-body perceived exertion without affecting contralateral performance. These findings highlight the task-specific and structure-dependent nature of non-local fatigue.

Key words: Crossover fatigue, jump, rebound, reactive strength index, power, contact time

Key Points
  • Unilateral dynamic fatigue of the dominant lower limb induced condition-dependent and transient impairments in contralateral lower-limb explosive performance, whereas upper-body explosive performance remained unaffected.
  • Continuous loading elicited measurable contralateral decrements, while the incorporation of brief recovery intervals mitigated these effects
  • Findings indicate that non-local fatigue is task-specific, centrally mediated, and highly sensitive to the fatiguing stimulus temporal organization (continuous vs. intermittent).
  • The rapid recovery supports a predominantly central mechanism and suggests that short recovery periods may be sufficient to restore explosive performance capacity.








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