TY - JOUR
T1 - A novel method to assess rate of force relaxation
T2 - reliability and comparisons with rate of force development across various muscles
AU - Mathern, Ryan M.
AU - Anhorn, Mitchel
AU - Uygur, Mehmet
N1 - Publisher Copyright:
© 2018, Springer-Verlag GmbH Germany, part of Springer Nature.
Copyright:
Copyright 2019 Elsevier B.V., All rights reserved.
PY - 2019/1/30
Y1 - 2019/1/30
N2 - Purpose: The ability to generate quick submaximal muscle forces followed by quick relaxations is essential for various athletic and daily tasks. While force generation has been studied extensively, the studies of force relaxation are scarce. Therefore, we aimed to develop the rate of force relaxation scaling factor (RFR-SF) as a kinetic variable to assess the ability to relax submaximal muscle forces quickly. Methods: Thirteen young adults performed rapid isometric force pulses to various submaximal levels in two different sessions. We compared RFR-SF with rate of development scaling factor (RFD-SF) in grip force muscles (GF), elbow (EE), and knee extensors (KE) and tested its reliability. Both RFD-SF and RFR-SF were calculated as the slopes of the linear relationship between peak forces and the corresponding peak rates of force development and relaxation, respectively. Results: RFR-SFs were mainly different among the tested muscle groups (GF 8.22 ± 0.76 1/s; EE 7.64 ± 0.92 1/s; KE 6.01 ± 1.75 1/s) and there was no correlation among them (all p > 0.05). Within each tested muscle group, RFR-SF was lower than RFD-SF (GF 9.29 ± 1.05 1/s; EE 10.75 ± 0.87 1/s; KE 9.66 ± 0.89 1/s; all p < 0.001). The reliability of RFR-SF was moderate to good across the tested muscles (ICCs between 0.54 and 0.76 and all CVs < 15%). Conclusion: The RFR-SF is a clinically relevant kinetic variable that can reliably quantify the ability to relax a muscle force quickly. Future studies should assess both RFD-SF and RFR-SF as they represent different properties of the neuromuscular system.
AB - Purpose: The ability to generate quick submaximal muscle forces followed by quick relaxations is essential for various athletic and daily tasks. While force generation has been studied extensively, the studies of force relaxation are scarce. Therefore, we aimed to develop the rate of force relaxation scaling factor (RFR-SF) as a kinetic variable to assess the ability to relax submaximal muscle forces quickly. Methods: Thirteen young adults performed rapid isometric force pulses to various submaximal levels in two different sessions. We compared RFR-SF with rate of development scaling factor (RFD-SF) in grip force muscles (GF), elbow (EE), and knee extensors (KE) and tested its reliability. Both RFD-SF and RFR-SF were calculated as the slopes of the linear relationship between peak forces and the corresponding peak rates of force development and relaxation, respectively. Results: RFR-SFs were mainly different among the tested muscle groups (GF 8.22 ± 0.76 1/s; EE 7.64 ± 0.92 1/s; KE 6.01 ± 1.75 1/s) and there was no correlation among them (all p > 0.05). Within each tested muscle group, RFR-SF was lower than RFD-SF (GF 9.29 ± 1.05 1/s; EE 10.75 ± 0.87 1/s; KE 9.66 ± 0.89 1/s; all p < 0.001). The reliability of RFR-SF was moderate to good across the tested muscles (ICCs between 0.54 and 0.76 and all CVs < 15%). Conclusion: The RFR-SF is a clinically relevant kinetic variable that can reliably quantify the ability to relax a muscle force quickly. Future studies should assess both RFD-SF and RFR-SF as they represent different properties of the neuromuscular system.
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U2 - 10.1007/s00421-018-4024-7
DO - 10.1007/s00421-018-4024-7
M3 - Article
C2 - 30367259
AN - SCOPUS:85055693536
VL - 119
SP - 291
EP - 300
JO - European Journal of Applied Physiology
JF - European Journal of Applied Physiology
SN - 1439-6319
IS - 1
ER -