Between-side differences in trunk rotational power in athletes trained in asymmetric sports.
The asymmetric loading of trunk muscles in sports like golf or tennis may cause side-to-side imbalances in rotational muscle strength and endurance. Such imbalances may be compounded by the presence of low back pain (LBP) and related injuries. However, trunk rotational power is a better predictor of athlete performance, and therefore its ability to reveal these asymmetries/dysbalances should be investigated.
This study compares peak and mean values of power during trunk rotations on the dominant and non-dominant side in golfers, ice-hockey players, tennis players, and an age-matched control group of fit individuals.
Groups of 17 golfers, 17 ice-hockey players, 21 tennis players, and 39 fit individuals performed standing trunk rotations to each side with a bar weight of 5.5, 10.5, 15.5, and 20 kg placed on the shoulders. Peak power and mean power in the acceleration phase of trunk rotations were measured using the FiTRO Torso Premium system.
Peak power and mean power in the acceleration phase of trunk rotations were significantly higher on the dominant (D) than non-dominant (ND) side at weights of 5.5 kg (14 and 14%), 10.5 kg (17 and 14%), 15.5 kg (16 and 15%), and 20 kg (16 and 16%) in ice-hockey players, at 5.5 kg (14 and 13%), 10.5 kg (17 and 14%), and 15.5 kg (15% – only peak power) in tennis players, and at 5.5 kg (17 and 18%) and 10.5 kg (19 and 17%) in golfers. However, their values did not differ significantly at these weights (< 10%) in the age-matched control group. The D/ND ratio was the highest in ice-hockey players (1.18, 1.19), followed by golfers (1.16, 1.17) and finally tennis players (1.12, 1.16).
Taking into account significantly higher trunk rotational power on the dominant than the non-dominant side in golfers, tennis players and ice-hockey players at lower and/or higher weights and no significant side-to-side differences in a control group of fit individuals, this parameter may be considered specific to their asymmetric loading during trunk rotations. However, whether these asymmetries/dysbalances expressed by the D/ND ratio could also identify the likelihood of LBP, needs to be proven.