Accuracy of Two Methods in Estimating Target Muscle Force During Shoulder Submaximal Isometric Contractions
# Background Submaximal isometric exercises are used for pain control and neuromuscular facilitation. Typically, an ipsilateral maximal voluntary isometric contraction (MVIC) is used as a reference; however, when this is not clinically feasible, an alternative must be considered. Two options are (1...
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| Main Authors: | , |
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| Format: | Article |
| Language: | English |
| Published: |
North American Sports Medicine Institute
2025-01-01
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| Series: | International Journal of Sports Physical Therapy |
| Online Access: | https://doi.org/10.26603/001c.127141 |
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| Summary: | # Background
Submaximal isometric exercises are used for pain control and neuromuscular facilitation. Typically, an ipsilateral maximal voluntary isometric contraction (MVIC) is used as a reference; however, when this is not clinically feasible, an alternative must be considered. Two options are (1) the no reference (NR) method (submaximal contraction at a self-perceived effort level without reference) and (2) the reciprocal reference (RR) method (MVIC on the contralateral side serves as a reference for a submaximal effort-level on the ipsilateral side). No research evidence exists as to which alternative method is more accurate at the shoulder.
# Purpose
To determine the accuracy of the NR and RR methods in estimating target muscle force during shoulder ER and IR submaximal isometric contractions among healthy adults.
# Study Design
Observational cross-sectional
# Methods
Isometric shoulder force was measured via a hand-held dynamometer on 48 healthy participants (36 females and 12 males) mean age of 27.4 ±1.6 years. Both methods (NR and RR), direction of force (IR and ER), and starting test-side (right or left) were randomized. RR testing involved a contralateral MVIC (reference) prior to a 50% submaximal contraction. NR testing entailed a 50% submaximal contraction with no prior reference MVIC.
# Results
Actual submaximal efforts were compared to MVIC-based estimated submaximal efforts. Significant moderate - good correlations existed for both the RR (r = 0.691) and NR (r = 0.620) methods, regardless of test-side or shoulder motion. Significant moderate - good correlations were found between both methods for both ER \[RR (r = 0.717) and NR (r = 0.614)\] and IR \[RR (r = 0.669) and NR (r = 0.628)\].
# Conclusion
Both methods had moderate - good accuracy levels and were not influenced by the test side or direction of force. Either method (RR or NR) can be equally useful for shoulder isometric exercise prescription when an ipsilateral reference cannot be determined.
# Level of Evidence
3 |
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| ISSN: | 2159-2896 |