The Effect of Unicycle Riding Course on Trunk Strength and Trunk Stability Functions in Children

The relationship between lower limb maximal and explosive strength and change of direction ability: Comparison of basketball and tennis players, and long-distance runners

Change-of-direction (CoD) ability is an important determinant of athletic performance. Muscle strength is among the most important determinants of CoD ability. However, previous studies investigating the relationship between CoD ability and muscle strength focused mostly on flexor and extensor muscle groups, or used multi-joint exercises, such as jumps, squats or mid-thigh pull. The purpose of the present study was to investigate the relationship between CoD ability and strength of ankle, knee, hip and trunk maximal and explosive strength. The participants (n = 327), consisting of male and female basketball players, tennis players and long-distance runners completed isometric strength assessments and CoD testing (90° and 180° turn tests). The times of both CoD tests were associated with muscle strength (peak torques and the rate of torque development variables), with correlation coefficients being mostly weak to moderate (r = 0.2–0.6). Strength variables explained 33%, 62% and 48% of the variance in the 90° turn task, and 42%, 36% and 59% of the variance in the 180° turn task, in basketball players, long-distance runners and tennis players, respectively. Hip and trunk muscle strength variables were the most prevalent in the regression models, especially hip adduction and abduction strength. Our results suggest that the strength of several lower limb muscles, in particular of the hip abductors and adductors, and trunk muscles, but also hip rotators, extensors and flexors, as well as knee and ankle flexors and extensors should be considered when aiming to improve CoD performance.

Increased Liveliness of Trunk Muscle Responses in Elite Kayakers and Canoeists

Trunk stability functions play an important role in sport and everyday movements. The aim of this study was to analyze trunk strength, trunk muscles onset of activity, and rate of electromyographic rise (RER) in the case of self-inflicted and unexpected trunk loading. Thirty-two healthy young adults (16 elite kayakers/canoeists and 16 non-athletes) were measured with a multi-purpose diagnostic machine. Trunk strength was assessed in standing position. Trunk muscles onset of activity and RER were assessed through unexpected loading over the hands and rapid shoulder flexion, respectively. In comparison with non-athletes, kayakers/canoeists did not significantly differ in trunk strength and showed lower trunk extension/flexion strength ratio (p = 0.008). In general, trunk muscles onset of activity did not significantly differ between the groups. On the contrary, kayakers/canoeists showed higher RER mean values in all the observed muscles (p < 0.041), except in multifidus muscle during self-inflicted movements. Similarly, higher RER variability was observed in the majority of the observed muscles among kayakers/canoeists. Higher RER among kayakers/canoeists could represent a protective mechanism that ensures spine stability and prevents low back pain.