Reliability of the assessment of peripheral muscle fatigue induced by high-intensity intermittent exercise

Reliability of the assessment of peripheral fatigue induced in knee extensors by highintensity intermittent running exercise (HIE) was established in ten amateur soccer players (age: 18 ± 1, height: 178 ± 5 cm, weight: 68 ± 8 kg). METHODS: Transcutaneous electrical stimulations before and after HIE determined muscle contractile properties on three separate occasions (T1, T2 and T3), each separated by 7 days. RESULTS: No significant differences were noted for any of the parameters measured (P =0.101). The ICC values for peak torque (PT) varied from moderate to high, with the exception of PT at 10Hz calculated comparing T2 vs T1 (range PRE =0.780.92; POST =0.760.97). The ICC derived from PT percentage decrements data were all low, with the exception of PT decrements at 1 Hz calculated comparing T3 vs T2(ICC =0.85, moderate). The TE for all contractile parameters obtained using 1Hz and 100Hz electrical stimulations were below 10%, including some that demonstrated a TE lower than 5%. Muscle contractile properties determined using 10Hz stimulations showed a higher level of TE (range: 3.215.1%). Similar results were obtained for maximal rate of torque development and torque relaxation. CONCLUSION: From the results of this study it can be concluded that muscle contractile properties express a good level of reliability in baseline and postexercise measures following familiarization.