This study analyzed the normality and variability of the data outputs of isokinetic endurance parameters in 10 healthy men and 10 healthy women. The test consisted of 25 maximal reciprocal contractions of the hamstring and quadriceps muscles. In addition, half of the subjects underwent a 7-week training period after which the endurance test was repeated. The results showed that the consistency of the absolute endurance measurements (work performed during the last 5 repetitions [WL5] and total work during 25 repetitions [TW25] was equal to that of the reference parameter, the peak torque. In addition, the changes after 7 weeks training were very similar; values for all these parameters increased significantly. The relative endurance parameter (WL5/work during the first 5 repetitions) did not change due to training since both WL5 and WF5 improved approximately the same amount. In conclusion, the absolute measurements of muscular endurance can be recommended for clinical use, while the endurance index should not be used routinely.
Pekka Kannus is with Tampere Research Station of Sports Medicine, Kaupinpuistonkatu 1, SF-33500 Tampere, Finland. At the time of this study the authors were with the Dept. of Orthopaedics & Rehabilitation, University of Vermont, Burlington, VT 05401.