Is perceived force an accurate method of regulating exercise load for the neck?

• Published in: Physiotherapy theory and practice Vol. 35; no. 6; pp. 596 - 601
• Main Authors: O'Leary, PT, PhD, Shaun, Cush, PT, Adrian M, Ng, PT, Woon Yang W, Taanevig, PT, Charlotte, Tan, PT, Jiahui E, McPhail, PT, PhD, Steven M
• Format: Journal Article
• Language: English
• Published: England 03-06-2019
• Subjects: rehabilitation; Cervical muscles; perceived force; isometric exercise
• ISSN: 0959-3985; 1532-5040
• DOI: 10.1080/09593985.2018.1455250

Patient perceived level of force is commonly used to regulate exercise load. This study determined the accuracy of perceived force as a method of regulating exercise load for the cervical flexors and extensors.
Thirty healthy individuals performed submaximal isometric cervical flexion and extension exercise at perceived intensities (25%, 50%, and 75%) of their maximal voluntary contraction (MVC) with no feedback in a neck dynamometer. Measurements of "actual" versus "perceived" force levels were compared before and after the performance of an MVC. Data were analyzed descriptively and the relationship between performance error, test, and participant factors examined.
With the exception of the 25% MVC extension trials post-MVC, an underestimation of force was observed over all conditions that worsened as the target force increased (50% and 75%) with only some improvement following the experience of an MVC (p < 0.001). Linear mixed modeling indicated participants familiar with exercise may have better accuracy (p = 0.07).
Regulating isometric resistance exercise load of the neck based on a perceived proportion of MVC force may only be accurate at low intensities (25% MVC) but not for moderate to high (50-75%) intensities.