BACKGROUND & OBJECTIVE
Neuromuscular control (NMC) has been suggested to be a modifiable risk factor for sports injury. Fatigue has also been shown to have a detrimental effect on NMC and there is some evidence to suggest that the effect could be age specific. This study looked at the effect of football (soccer)-specific fatigue on various aspects of neuromuscular control. As such, it is intended to be a paper to support a rationale underpinning appropriate conditioning to minimise fatigue-related changes, that could predispose to injury in sport. The authors linked this to knee and lower limb injuries in particular and in the context of a younger athlete population.
The authors looked at 18 healthy, elite 14-15 year old male footballers. Measures were taken before and after a fatigue protocol, which was a modified SAFT (soccer-specific aerobic field test) 90 protocol (2x35 mins), to adapt to the typical times of match play for this age group. The SAFT90 is a football specific shuttle test that includes various agility drills and changing intensity, in response to standardised commands.
They used Opto-jump to measure reactive strength during a typical 30cm drop jump and leg stiffness, during a trial of 20 jumps at a set frequency. Stiffness was calculated in kN/m, using a referenced, standardised approach. Concentric quads and hamstring strength was measured using an isokinetic dynamometer at 60/s, 180/s, 360/s. Absolute Peak Torque was collected in Nm. EMG activity of vastus medialis (VM), vastus lateralis (VL), rectus femoris (RF), medial and lateral hamstrings was recorded during strength testing.
There were significant reductions in EMG activity in RF, VM, medial hamstrings but not VL or lateral hamstrings. Reactive Strength Index, relative and absolute leg stiffness all showed significant decreases post-fatigue protocol. There were no significant differences in Hams/Quads ratios