The Initial Position of the Contralateral Leg Affects the Muscular Power Capability of Testing and Training on a Leg Press [Die Ausgangsstellung des kontralateralen Beines beeinflusst die muskul?re Kraftf?higkeit beim Testen und Trainieren auf einer Beinpresse]

摘要

There are numerous studies on the factors influencing the maximum isometric force. These include, among others, the activity of the contralateral extremities in unilateral measurements. With reference to this parameter, there is still disagreement. Some studies suggest that activation of the contralateral antagonist leads to an increase in force production of the tested limb. In contrast, other research groups came to the conclusion that simultaneous contraction of the contralateral agonists have this effect. The aim of this study was to find out how certain starting positions and contraction directions of the non-tested limb affect the force capability of the contralateral limb during unilateral maximum isometric force measurements on a leg press. In the course of the investigation, the unilateral isometric maximum force capacity of the lower limbs of 20 subjects in four different starting positions and forms of activation of the contralateral limb was tested. The non-tested leg was first loosely placed on the floor (starting position A), then it was held on the body in maximum knee and hip flexion (test situation G) and after that it had to perform maximal contraction exercises in extension (KE) and flexion (KF) each against a stabilisation bar. The results showed significantly (p < 0.05) lower force levels during the contralateral contraction KF compared to all other test situations. In the starting position A, the subjects reached the highest values. Compared to G and KF these differences in maximum force development were significant (p < 0.05). Both the initial position, and the activity of the contralateral limb has an impact on the maximum isometric extension strength of the tested leg at the leg press. Therefore, during the repeated execution of an isometric strength test on this apparatus, it should be taken care that the subject occupies the same starting position as the previous test. A voluntary activation of the contralateral side should be avoided during the measurement, or in the same way.