Term of Award

Spring 2015

Degree Name

Master of Science in Kinesiology (M.S.)

Document Type and Release Option

Thesis (restricted to Georgia Southern)

Copyright Statement / License for Reuse

Creative Commons License
This work is licensed under a Creative Commons Attribution 4.0 License.


Department of Health and Kinesiology

Committee Chair

John Dobson

Committee Member 1

Jim McMillan

Committee Member 2

Stephen Rossi


The purpose of this study was to compare the effects of various dosages of light emitting diode therapy (LEDT) on muscle fatigue, while performing a single leg extension to exhaustion. 34 recreationally resistance trained athletes between the ages of 18 and 26 participated in four trials. Each trial included pre and post exercise blood lactate measurements, two sets of three maximal voluntary isometric contractions (MVIC), followed by LEDT on six points across the superficial quadriceps. Each randomized trial consisted of a placebo, 30 seconds, 60 seconds or 120 seconds on each point on the quadriceps. Three minutes after LEDT, the participants performed an eccentric leg extension with 120% of MVIC until fatigue. There was significant increase in the number of repetitions performed between the placebo treatment and 60 seconds (p= 0.023), as well as placebo and 120 seconds (p=0.004) of irradiation on each point. There was no significant between blood lactate levels between all four trials. Even though there were no differences found in blood lactate measurements, LEDT appears to have a positive effect on performance when irradiating six points on the superficial quadriceps for 60 seconds and 120 seconds prior to an eccentric leg extension.