Chronic Sequelae After Muscle Strain Injuries: Influence of Heavy Resistance Training on Functional and Structural Characteristics in a Randomized Controlled Trial.

BACKGROUND: Muscle strain injury leads to a high risk of recurrent injury in sports and can cause long-term symptoms such as weakness and pain. Scar tissue formation after strain injuries has been described, yet what ultrastructural changes might occur in the chronic phase of this injury have not. It is also unknown if persistent symptoms and morphological abnormalities of the tissue can be mitigated by strength training. PURPOSE: To investigate if heavy resistance training improves symptoms and structural abnormalities after strain injuries. STUDY DESIGN: Randomized controlled trial; Level of evidence, 1. METHODS: A total of 30 participants with long-term weakness and/or pain after a strain injury of the thigh or calf muscles were randomized to eccentric heavy resistance training of the injured region or control exercises of the back and abdominal muscle. Isokinetic (hamstring) or isometric (calf) muscle strength was determined, muscle cross-sectional area measured, and pain and function evaluated. Scar tissue ultrastructure was determined from biopsy specimens taken from the injured area before and after the training intervention. RESULTS: Heavy resistance training over 3 months improved pain and function, normalized muscle strength deficits, and increased muscle cross-sectional area in the previously injured region. No systematic effect of training was found upon pathologic infiltration of fat and blood vessels into the previously injured area. Control exercises had no effect on strength, cross-sectional area, or scar tissue but a positive effect on patient-related outcome measures, such as pain and functional scores. CONCLUSION: Short-term strength training can improve sequelae symptoms and optimize muscle function even many years after a strain injury, but it does not seem to influence the overall structural abnormalities of the area with scar tissue. REGISTRATION: NCT02152098 (ClinicalTrials.gov identifier).

Corticosteroid injection is the best treatment in plantar fasciitis if combined with controlled training.

PURPOSE: Plantar fasciitis is a very common (lifetime incidence ~ 10%) and long-lasting injury with major impact on daily function. Combining corticosteroid injection and physical training (strength training and stretching) was hypothesized to result in a superior effect compared to each treatment separately. METHODS: A single blinded randomized controlled superiority trial conducted in 2013-2014 with a 2-year follow-up (end Sept 2016). 123 consecutive patients (20-65 years) referred to two study centers in Denmark: Institute of Sports Medicine, Bispebjerg Hospital, University of Copenhagen and a private rheumatology clinic with symptoms of plantar fasciitis, and ultrasound measured thickness above 4.0 mm were invited. 25 did not fulfill the inclusion criteria (mainly ultrasound criteria) and 8 refused participation. 90 patients were randomized (pulling sealed envelopes) to 3 groups: (1) 3 months strength training and stretching (n = 30), (2) corticosteroid injections with monthly intervals until thickness < 4.0 mm (maximum 3 injections) (n = 31), (3) combination of the two treatments (n = 29). During the 3 months intervention period load reduction was recommended (cushioning shoes and insoles and abstaining from running and jumping). The main outcome was improvement in Pain at function on a 100-mm VAS score and in Foot Function Index (FFI, range 0-230) at 6 months (Clinicaltrials.gov Identifier: NCT01994759). RESULTS: All groups improved significantly over time, but the combination of corticosteroid injection and training (strength training and stretching) had a superior effect at all time points. The mean difference between the combined treatment and training was 40 points in FFI (95% confidence interval (CI) 63-17 points, p < 0.001) and 20 mm for VAS function pain (CI 35-5 mm, p < 0.01). The mean difference between the combined treatment and corticosteroid injections only was 29 points in FFI (CI 52-7 points, p < 0.01) and 17 mm for VAS function pain (CI 32-2 mm, p < 0.05). All differences were clinically relevant. CONCLUSION: The best treatment for plantar fasciitis is the combination of corticosteroid injections and training (strength training and stretching). This combined treatment is superior both in the short- and in the longterm. Corticosteroid injections combined with controlled training are recommended as first line treatment in patients with plantar fasciitis. LEVEL OF EVIDENCE: 1.