-Effects of Focal Knee Joint Cooling on Spectral Properties of Rectus Femoris and Vastus Lateralis Electromyography

Submitted: 3/1/09; Accepted: 5/6/09; Posted: 6/9/09

This article investigates the effects of a 20-minute knee joint cooling intervention on vastus lateralis and rectus femoris activation during maximal voluntary isometric contractions (MVIC). Eleven healthy individuals (6 men, 5 women; mean age = 25±5 years, mean height = 171±10 cm, mean weight = 77±21 kg) volunteered for this crossover study. The order of the 2 treatment groups (knee joint cooling and control) were completed 3 to 14 days apart. Electromyography (EMG) measurements were collected in the vastus lateralis and rectus femoris at 4 separate times (baseline and 20, 30, and 45 minutes postintervention) during a knee extension MVIC at 70°. Vastus lateralis EMG was significantly greater during the cooling condition, compared with the control at 20 minutes (10.69±13.2 versus –16±24.00; t10 = 2.609, P = .026) and 45 minutes after treatment (2.76±19.28 versus –24.06±27.88; t10 = 3.234, P = .009). A significant increase in vastus lateralis EMG following a 20-minute joint cooling at 20 and 45 minutes postintervention existed, compared with the control condition.