High-intensity strength training improves function of chronically painful muscles: case-control and RCT studies.
OBJECTIVE
This study investigates consequences of chronic neck pain on muscle function and the rehabilitating effects of contrasting interventions.


METHODS
Women with trapezius myalgia (MYA, n = 42) and healthy controls (CON, n = 20) participated in a case-control study. Subsequently MYA were randomized to 10 weeks of specific strength training (SST, n = 18), general fitness training (GFT, n = 16), or a reference group without physical training (REF, n = 8). Participants performed tests of 100 consecutive cycles of 2 s isometric maximal voluntary contractions (MVC) of shoulder elevation followed by 2 s relaxation at baseline and 10-week follow-up.


RESULTS
In the case-control study, peak force, rate of force development, and rate of force relaxation as well as EMG amplitude were lower in MYA than CON throughout all 100 MVC. Muscle fiber capillarization was not significantly different between MYA and CON. In the intervention study, SST improved all force parameters significantly more than the two other groups, to levels comparable to that of CON. This was seen along with muscle fiber hypertrophy and increased capillarization.


CONCLUSIONS
Women with trapezius myalgia have lower strength capacity during repetitive MVC of the trapezius muscle than healthy controls. High-intensity strength training effectively improves strength capacity during repetitive MVC of the painful trapezius muscle.
National Research Centre for the Working Environment, Lersø Parkalle 105, 2100 Copenhagen, Denmark.
Lars L
0000-0003-2777-8085
LL
Andersen
National Research Centre for the Working Environment, Lersø Parkalle 105, 2100 Copenhagen, Denmark.
Christoffer H
CH
Andersen
National Research Centre for the Working Environment, Lersø Parkalle 105, 2100 Copenhagen, Denmark.
Jørgen H
JH
Skotte
Section of Clinical Physiology and Nuclear Medicine, Department of Diagnostics, Glostrup Hospital, University of Copenhagen, 2600 Glostrup, Denmark.
Charlotte
C
Suetta
Institute of Sport Science and Clinical Biomechanics, University of Southern Denmark, Campusvej 55, 5230 Odense M, Denmark.
Karen
K
Søgaard
Copenhagen Muscle Research Centre, University of Copenhagen, 2100 Copenhagen, Denmark.
Bengt
B
Saltin
Institute of Sport Science and Clinical Biomechanics, University of Southern Denmark, Campusvej 55, 5230 Odense M, Denmark.
Gisela
G
Sjøgaard
D016022:Case-Control Studies; D059350:Chronic Pain / Q000503:physiopathology* / Q000628:therapy*; D015444:Exercise / Q000502:physiology*; D005260:Female; D006801:Humans; D006984:Hypertrophy / Q000503:physiopathology / Q000628:therapy; D009119:Muscle Contraction / Q000502:physiology; D018485:Muscle Fibers, Skeletal / Q000502:physiology*; D063806:Myalgia / Q000503:physiopathology* / Q000628:therapy*; D019547:Neck Pain / Q000503:physiopathology / Q000628:therapy; D055070:Resistance Training / Q000379:methods; D064171:Superficial Back Muscles / Q000503:physiopathology*