BACKGROUND Increasing quadriceps:hamstring muscular co-contraction at the knee may reduce the risk of anterior cruciate ligament (ACL) injury. The purpose of this investigation was to examine muscle activation in the quadriceps and hamstrings and peak kinematics of the knee, hip, and trunk when performing a single-leg drop (SLD) on to a Bosu ball (unstable surface) compared with on to the floor...

Abstract Background Evidence suggests that neuromuscular alterations in patients with an anterior cruciate ligament reconstruction (ACLR) are rooted neurocognitive and proprioceptive deficits. The aim of this study was to assess control athletes ACLR under increased cognitive environmental challenges. Research question Do show a different response challenges relative controls? Methods Cross-sec...

Eight patients with patellar pain underwent knee proprioceptive training. The maximal knee extension torque associated with the Vastus Lateralis EMG signal increased (p 0.001 and 0.039). Although muscle balance was not improved, all the patients improved their clinical scores.

[Purpose] The purpose of the present study was to examine the effects of squat exercises performed on different surfaces on the activity of the quadriceps femoris muscle in order to provide information on support surfaces for effective squat exercises. [Subjects and Method] Fourteen healthy subjects performed squat exercises for five seconds each on three different support surfaces: hard plates...

Textile electromyography (EMG) electrodes embedded in clothing allow muscle excitation to be recorded in previously inaccessible settings; however, their ability to accurately and reliably measure EMG during dynamic tasks remains largely unexplored. To quantify the validity and reliability of textile electrodes, 16 recreationally active males completed two identical testing sessions, within whi...

The origin of the slow component (SC) of oxygen uptake kinetics, presenting during exercise above the ventilatory threshold (VT), remains unclear. Possible physiologic mechanisms include a progressive recruitment of type II muscle fibers. The purpose of this study was to examine alterations in muscle activity through electromyography (EMG) and mean power frequency (MPF) analysis during heavy cy...

The objective of this study was to compare the electromyographic (EMG) activity of vastus medialis obliquus (VMO), vastus lateralis longus (VLL) and vastus lateralis oblíquus (VLO) during wall slide squat isometric exercises at 45° (WS 45°) and at 60° (WS 60°) of knee flexion. Fifteen healthy control women and fifteen women with patellofemoral pain syndrome (PPS) participated in this study. The...

The current study examined the effects of using an unstable surface during whole-body vibration (WBV) exercise on leg and trunk muscle activity during a static semi-squat. Twenty-eight recreationally active university students completed 4 different test conditions: 1) stable surface with no WBV; 2) unstable surface with no WBV; 3) unstable surface with 30 Hz WBV low amplitude; and 4) unstable s...