Kinematics, kinetics, and electromyogram of ankle during drop landing: a comparison between dominant and non-dominant limb

The biomechanical difference between the dominant and non-dominant limb has seldom been studied during double-leg landing. The objective of this study was to evaluate the effectiveness of limb laterality on the ankle kinematics, kinetics and electromyogram (EMG) during drop landing. Sixteen healthy adults were recruited and dropped individually from platforms with three different heights (0.32 m, 0.52 m, and 0.72 m). The ground reaction force, ankle joint kinematics, and surface EMG of tibialis anterior (TA) and lateral gastrocnemius (LG) were measured in both lower extremities. Two-way analysis of variance was used to analyze the effects of laterality and dropping height. The peak angular velocities in dorsiflexion and abduction were significantly higher in the dominant ankle, whereas the pre- and post-landing EMG amplitudes of the TA were significantly higher in the non-dominant limb. Compared with the dominant side, the non-dominant ankle has a more effective protective mechanism in that excessive joint motion is restrained by greater ankle flexor activity. Compared with the non-dominant side, the dominant ankle joint is in greater injury risk during drop landing, and data measured in the dominant limb may produce more conservative conclusions for injury protection or prediction.     

Motivation for physical activity in children: A moving matter in need for study

Motivation for physical activity in children below the age of 12 years is a largely underrepresented issue in contemporary research. Although engagement in sufficient physical activity is highly important for children’s current and later health, relatively little is known of the factors that motivate children to be physically active. Various theories have been developed in an attempt to explain motivation toward physical activity in adults. Recent developments have focussed on integrating constructs of these theories in order to attain a comprehensive account of motivated behavior. The relationships between different motivational constructs have generally been investigated in healthy adolescents and adults.