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Toninelli N, Coratella G, Longo S, Romani GM, Doria C, Rampichini S, Limonta E, Esposito F, Cè E. Synergistic difference in the effect of stretching on electromechanical delay components. PLoS One 2024; 19:e0300112. [PMID: 38530855 DOI: 10.1371/journal.pone.0300112] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2023] [Accepted: 02/21/2024] [Indexed: 03/28/2024] Open
Abstract
This study investigated the synergistic difference in the effect of stretching on electromechanical delay (EMD) and its components, using a simultaneous recording of electromyographic, mechanomyographic, and force signals. Twenty-six healthy men underwent plantar flexors passive stretching. Before and after stretching, the electrochemical and mechanical components of the EMD and the relaxation EMD (R-EMD) were calculated in gastrocnemius medialis (GM), lateralis (GL) and soleus (SOL) during a supramaximal motor point stimulation. Additionally, joint passive stiffness was assessed. At baseline, the mechanical components of EMD and R-EMD were longer in GM and GL than SOL (Cohen's d from 1.78 to 3.67). Stretching decreased joint passive stiffness [-22(8)%, d = -1.96] while overall lengthened the electrochemical and mechanical EMD. The mechanical R-EMD components were affected more in GM [21(2)%] and GL [22(2)%] than SOL [12(1)%], with d ranging from 0.63 to 1.81. Negative correlations between joint passive stiffness with EMD and R-EMD mechanical components were found before and after stretching in all muscles (r from -0.477 to -0.926; P from 0.007 to <0.001). These results suggest that stretching plantar flexors affected GM and GL more than SOL. Future research should calculate EMD and R-EMD to further investigate the mechanical adaptations induced by passive stretching in synergistic muscles.
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Affiliation(s)
- Nicholas Toninelli
- Department of Biomedical Sciences for Health (SCIBIS), Università degli Studi di Milano, Milan, Italy
| | - Giuseppe Coratella
- Department of Biomedical Sciences for Health (SCIBIS), Università degli Studi di Milano, Milan, Italy
| | - Stefano Longo
- Department of Biomedical Sciences for Health (SCIBIS), Università degli Studi di Milano, Milan, Italy
| | - Giulia M Romani
- Division of Exercise Physiology, School of Medicine, West Virginia University, Morgantown, West Virginia, United States of America
| | - Christian Doria
- Department of Biomedical Sciences for Health (SCIBIS), Università degli Studi di Milano, Milan, Italy
| | - Susanna Rampichini
- Department of Biomedical Sciences for Health (SCIBIS), Università degli Studi di Milano, Milan, Italy
| | - Eloisa Limonta
- Department of Biomedical Sciences for Health (SCIBIS), Università degli Studi di Milano, Milan, Italy
| | - Fabio Esposito
- Department of Biomedical Sciences for Health (SCIBIS), Università degli Studi di Milano, Milan, Italy
- Division of Exercise Physiology, School of Medicine, West Virginia University, Morgantown, West Virginia, United States of America
- IRCSS Galeazzi Orthopedic Institute, Milan, Italy
| | - Emiliano Cè
- Department of Biomedical Sciences for Health (SCIBIS), Università degli Studi di Milano, Milan, Italy
- Division of Exercise Physiology, School of Medicine, West Virginia University, Morgantown, West Virginia, United States of America
- IRCSS Galeazzi Orthopedic Institute, Milan, Italy
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Mechanisms underlying performance impairments following prolonged static stretching without a comprehensive warm-up. Eur J Appl Physiol 2020; 121:67-94. [PMID: 33175242 DOI: 10.1007/s00421-020-04538-8] [Citation(s) in RCA: 49] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2020] [Accepted: 10/21/2020] [Indexed: 01/28/2023]
Abstract
Whereas a variety of pre-exercise activities have been incorporated as part of a "warm-up" prior to work, combat, and athletic activities for millennia, the inclusion of static stretching (SS) within a warm-up has lost favor in the last 25 years. Research emphasized the possibility of SS-induced impairments in subsequent performance following prolonged stretching without proper dynamic warm-up activities. Proposed mechanisms underlying stretch-induced deficits include both neural (i.e., decreased voluntary activation, persistent inward current effects on motoneuron excitability) and morphological (i.e., changes in the force-length relationship, decreased Ca2+ sensitivity, alterations in parallel elastic component) factors. Psychological influences such as a mental energy deficit and nocebo effects could also adversely affect performance. However, significant practical limitations exist within published studies, e.g., long-stretching durations, stretching exercises with little task specificity, lack of warm-up before/after stretching, testing performed immediately after stretch completion, and risk of investigator and participant bias. Recent research indicates that appropriate durations of static stretching performed within a full warm-up (i.e., aerobic activities before and task-specific dynamic stretching and intense physical activities after SS) have trivial effects on subsequent performance with some evidence of improved force output at longer muscle lengths. For conditions in which muscular force production is compromised by stretching, knowledge of the underlying mechanisms would aid development of mitigation strategies. However, these mechanisms are yet to be perfectly defined. More information is needed to better understand both the warm-up components and mechanisms that contribute to performance enhancements or impairments when SS is incorporated within a pre-activity warm-up.
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