Passive muscle stretching impairs rapid force production and neuromuscular function in human plantar flexors
We examined the effect of muscle stretching on the ability to produce rapid torque and the mechanisms underpinning the changes.
Eighteen men performed three conditions: (1) continuous stretch (1 set of 5 min), (2) intermittent stretch (5 sets of 1 min with 15-s inter-stretch interval), and (3) control. Isometric plantar flexor rate of torque development was measured during explosive maximal voluntary contractions (MVC) in the intervals 0–100 ms (RTDV100) and 0–200 ms (RTDV200), and in electrically evoked 0.5-s tetanic contractions (20 Hz, 20 Hz preceded by a doublet and 80 Hz). The rate of EMG rise, electromechanical delay during MVC (EMDV) and during a single twitch contraction (EMDtwitch) were assessed.
RTDV200 was decreased (P < 0.05) immediately after continuous (− 15%) and intermittent stretch (− 30%) with no differences between protocols. The rate of torque development during tetanic stimulations was reduced (P < 0.05) immediately after continuous (− 8%) and intermittent stretch (− 10%), when averaged across stimulation frequencies. Lateral gastrocnemius rate of EMG rise was reduced after intermittent stretch (− 27%), and changes in triceps surae rate of EMG rise were correlated with changes in RTDV200 after both continuous (r = 0.64) and intermittent stretch (r = 0.65). EMDV increased immediately (31%) and 15 min (17%) after intermittent stretch and was correlated with changes in RTDV200 (r = − 0.56). EMDtwitch increased immediately after continuous (4%), and immediately (5.4%), 15 min (6.3%), and 30 min after (6.4%) intermittent stretch (P < 0.05).
Reductions in the rate of torque development immediately after stretching were associated with both neural and mechanical mechanisms.
KeywordsRate of force development Explosive force Flexibility Force transmission
Analysis of variance
Electromechanical delay during the electrically evoked twitch
Electromechanical delay during voluntary contraction
Maximal compound action potential amplitude
Maximal voluntary contraction
Persistent inward currents
Rate of electromyogram rise
Rate of force development
Rate of torque development
Involuntary rate of torque development
Voluntary rate of torque development
Variable-frequency train of stimulation
GST and AJB conceived and designed the study. GST and LS conducted the experiments. GST analyzed the data, and drafted the first version of the manuscript. GST, LB, KN, and AJB critically revised the manuscript. All authors read and approved the manuscript.
This research received no specific grant from any funding agency in the public, commercial or not-for-profit sectors.
Compliance with ethical standards
Conflict of interest
No conflicts of interest, financial or otherwise, are declared by the author(s).
- Cohen J (1988) Statistical power analysis for the behavioral sciences, 2nd edn. L. Erlbaum Associates, Hillsdale, N.JGoogle Scholar
- Esposito F, Limonta E, Cè E (2011) Passive stretching effects on electromechanical delay and time course of recovery in human skeletal muscle: new insights from an electromyographic and mechanomyographic combined approach. Eur J Appl Physiol 111:485–495. https://doi.org/10.1007/s00421-010-1659-4 CrossRefPubMedGoogle Scholar
- Lanza MB, Balshaw TB, Folland JP (2017) MMAX normalisation of voluntary EMG removes the confounding influences of electrode location and body fat. Med Sci Sport Exerc 49:779. https://doi.org/10.1249/01.mss.0000519076.74034.cb CrossRefGoogle Scholar