Detecting fatigue thresholds from electromyographic signals: A systematic review on approaches and methodologies

The aim of the current paper was to systematically review the relevant existing electromyographic threshold concepts within the literature. The electronic databases MEDLINE and SCOPUS were screened for papers published between January 1980 and April 2015 including the keywords: neuromuscular fatigue threshold, anaerobic threshold, electromyographic threshold, muscular fatigue, aerobic-anaerobictransition, ventilatory threshold, exercise testing, and cycle-ergometer. 32 articles were assessed with regard to their electromyographic methodologies, description of results, statistical analysis and test protocols. Only one article was of very good quality. 21 were of good quality and two articles were of very low quality. The review process revealed that: (i) there is consistent evidence of one or two non-linear increases of EMG that might reflect the additional recruitment of motor units (MU) or different fiber types during fatiguing cycle ergometer exercise, (ii) most studies reported no statistically significant difference between electromyographic and metabolic thresholds, (iii) one minute protocols with increments between 10 and 25W appear most appropriate to detect muscular threshold, (iv) threshold detection from the vastus medialis, vastus lateralis, and rectus femoris is recommended, and (v) there is a great variety in study protocols, measurement techniques, and data processing. Therefore, we recommend further research and standardization in the detection of EMGTs.

Retesting the validity of a specific field test for judo training

The main goal of this research project was to retest the validity of a specifically designed judo field test (Santos Test) in a different group of judokas. Eight (n=8) national-level male judokas underwent laboratory and field testing. The mean data (mean +/− SD) obtained in the laboratory tests was: HR_max: 200 ± 4.0 beats × min⁻¹, VO_{2 max}: 52.8 ± 7.9 ± ml × kg⁻¹ × min⁻¹, lactate max: 12 ± 2.5 mmol × l⁻¹, HR at the anaerobic threshold: 174.2 ± 9.4 beats × min⁻¹, percentage of maximum heart rate at which the anaerobic threshold appears: 87 ± 3.6 %, lactate threshold: 4.0 ± 0.2 mmol × l⁻¹, and RPE: 17.2 ± 1.0. The mean data obtained in the field test (Santos) was: HR_max: 201.3 ± 4.1 beats × min⁻¹, VO_{2 max}: 55.6 ± 5.8 ml × kg⁻¹ × min⁻¹, lactate max: 15.6 ± 2.8 mmol × l⁻¹, HR at the anaerobic threshold: 173.2 ± 4.3 beats × min⁻¹, percentage of maximum heart rate at which the anaerobic threshold appears: 86 ± 2.5 %, lactate threshold: 4.0 ± 0.2 mmol × l⁻¹, and RPE: 16.7 ± 1.0. There were no significant differences between the data obtained on both tests in any of the parameters, except for maximum lactate concentration. Therefore, the Santos test can be considered a valid tool specific for judo training.