Long Jump Performance Is Not Related to Inter-Limb Asymmetry in Force Application in Isometric and Vertical Jump Tests

Abstract

The aim of the study was to examine the inter-limb asymmetry in force application in a 1-s maximum isometric leg press test (ISOM) and vertical jump tests without an arm swing (VJ)of male long jumpers. Nine experienced jumpers (age: 18–30 y, LJ personal best: 6.50–8.05 m) were examined. Participants performed: (a) bilateral VJs from the squatting position (SQJ) and with a countermovement (CMJ), (b) unilateral CMJ from the take-off (TOL) and swing (SWL) leg used in the LJ take-off, and c) bilateral 1-s ISOM tests. Data were collected for each lower limb with separate force dynamometers (sampling frequency: VJs = 1 kHz, ISOM = 500 Hz). The inter-limb asymmetry of the peak applied force was evaluated using the symmetry angle. The paired samples T-test revealed non-significant (p > 0.05) inter-limb differences for the force output in the bilateral jump tests, in the unilateral jump tests, and in the ISOM. In conclusion, despite the fact that a powerful unilateral take-off is required for the optimization of long jump performance, no asymmetry was found in the examined tests, suggesting that the dominant/take-off leg was not stronger than the contra-lateral leg. This is possibly due to the intensive execution of other bilateral tasks involved, like the approach run.

Inter-Limb Asymmetry in the Kinematic Parameters of the Long Jump Approach Run in Female Paralympic-Level Class T63/T64 Athletes

“…The approach lane was calibrated using custom 5 × 5 cm reference markers. These markers were attached to the track surface at both sides of the runway's lines, creating 1.00 × 1.30 m reference zones [13]. Every competition attempt of the participants was recorded with a high-speed digital camera (Exilim-Pro-EX-F1, Casio Computer Co. Ltd., Shibuya, Japan; sampling rate: 300 fps; resolution: 512 × 384 pixels).…”

“…During the take-off, a considerable amount of loading is imposed on the lower limb that is used as the take-off leg, due to the applied vertical ground reaction forces [12]. As this considerable load is applied only to the take-off leg, the long jump is generally characterized as an asymmetrical sports activity because of the unilateral execution of the take-off [13].…”

“…Past research has provided evidence for the existence of a relationship between interlimb asymmetry and injury in track and field long jumpers [22][23][24], since larger inter-limb asymmetry was found in track and field jumpers compared to athletes with a bilateral pattern of sport movement [25]. However, there is bias in the literature, as no significant differences were revealed in terms of force parameters between the take-off and the swing leg in athletes competing in athletics jumping events [13,26]. When examining the event per se, namely the execution of the long jump approach, significant inter-limb asymmetry in step frequency (SF) and SL was reported in a considerable number of able-bodied jumpers [6].…”