Immediate Effects of Transcutaneous Electrical Nerve Stimulation and Focal Knee Joint Cooling on Quadriceps Activation

PIETROSIMONE, BRIAN G.1; HART, JOSEPH M.2; SALIBA, SUSAN A.1; HERTEL, JAY1; INGERSOLL, CHRISTOPHER D.1

Medicine & Science in Sports & Exercise: June 2009 - Volume 41 - Issue 6 - pp 1175-1181
doi: 10.1249/MSS.0b013e3181982557
Clinical Sciences

Purpose: To determine whether transcutaneous electrical nerve stimulation (TENS) and focal knee joint cooling will affect the quadriceps central activation ratio (CAR) in patients with tibiofemoral osteoarthritis.

Methods: Thirty-three participants with diagnosed tibiofemoral osteoarthritis were randomly allocated to the 45-min TENS treatment (six males and four females, 56 ± 10.1 yr, 174.11 ± 10.78 cm, 89.34 ± 21.3 kg), the 20-min focal knee joint cooling treatment (six males and five females, 58 ± 8.4 yr, 176.41 ± 8.29 cm, 83.18 ± 17.97 kg), or the control group (five males and seven females, 54 ± 9.9 yr, 166.37 ± 13.07 cm, 92.14 ± 25.37 kg). Volitional quadriceps activation, maximal voluntary isometric contraction, and subjective pain measurements were conducted at baseline and at 20, 30, and 45 min. The 20-min focal knee joint cooling intervention consisted of two 1.5-L ice bags to the anterior and posterior aspects of the knee. The TENS group received 45 min of a sensory, biphasic square wave stimulation (150-μs phase duration and 150 pps) from four 2 × 2-inch electrodes positioned around the patella.

Results: TENS resulted in a significantly higher percent change in CAR scores compared with control at 20 min (6.4 ± 4.8 vs −3.5 ± 8, P = 0.006), 30 min (9.7 ± 10.16 vs −1 ± 7.9, P = 0.025), and 45 min (11.25 ± 6.96 vs 0.81 ± 9.4, P = 0.029). Focal knee joint cooling resulted in significantly higher percent change scores compared with the control group at 20 min (5.75 ± 7.25 vs −3.5 ± 8, P = 0.009) and trended to be higher at 45 min (9.06 ± 9.63 vs 0.81 ± 9.4, P = 0.098). No significant differences in percent change for CAR were found between the TENS and the focal knee joint cooling group.

Conclusions: Both TENS and focal knee joint cooling increased the quadriceps CAR immediately after application in participants with tibiofemoral osteoarthritis.

1Exercise and Sport Injury Laboratory, University of Virginia, Charlottesville, VA; and 2Department of Orthopaedic Surgery, University of Virginia, Charlottesville, VA

Address for correspondence: Christopher D. Ingersoll, Ph.D., A.T.C., F.A.C.S.M., F.N.A.T.A., 210 Emmet St South, PO Box 400407, Charlottesville, VA 22904-4407; E-mail: Ingersoll@virginia.edu.

Submitted for publication September 2008.

Accepted for publication December 2008.

©2009The American College of Sports Medicine