Research Review By Jessica Sleeth©

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Date Posted:

October 2012

Study Title:

Resistance training in musculoskeletal rehabilitation: a systematic review

Authors:

Kristensen J, Franklyn-Miller A

Author's Affiliations:

Centre for Human Performance, Rehabilitation and Sports Medicine, Defence Medical Rehabilitation Centre Headley Court, Epsom, Surrey, UK

Publication Information:

British Journal of Sports Medicine 2012; 46: 719-726

Background Information:

Resistance training (RT) has been validated as a useful modality in healthy populations to increase muscle size, maximal strength, and functional ability. Yet, little is known about the effects of RT on injured populations, and guidelines for optimal use do not currently exist.

The objective for this review is to summarize the effects of RT in a rehabilitation context with regards to its effects on: maximal strength, functional ability, alleviation of pain, and quality of life parameters in the musculoskeletal conditions where RT is most commonly prescribed.

Pertinent Results:

Chronic Low Back Pain:
Chronic low back pain (CLBP) is the most common musculoskeletal condition that affects both athletic and non-athletic individuals. In general, the etiology of CLBP is multifactorial, but a common factor appears to be deconditioning of the extensor muscles of the back, causing a loss of muscle strength (1). Resistance training (RT) has been documented to improve muscle strength and reduce self-reported pain in patients with CLBP (2-6). Long-term benefits of RT interventions have been reported (7) and may also be influenced by extrinsic factors such as physical activity, smoking, and treatment outcome expectations (8).

Important features of RT programs pertinent to rehabilitation include the training intensity, volume, periodization and type of contraction:
  • Contraction type: Sertpoyraz et al. (9) reported increased lumbar extension strength and reduced self-reported pain in patients who participated in an isokinetic RT program, however, the results were not significant when compared to a standard treatment program. Evidence appears to be conflicting regarding the optimal type of contraction for CLBP rehabilitation.
  • Volume: The review of training volume recommendations is not conclusive. Limke et al. (10) reported that completing 2 sets of exercises instead of 1 set did not significantly change self-reported pain or muscular strength. However, the RT program included 6 different strengthening exercises, thus the accumulated training volume was higher; making the study results inconclusive.
  • Intensity: The studies reviewed did not find that high-intensity RT programs elicited beneficial results, however, the level of intensity used was different than what is used in healthy populations. The RT programs used 50% of 1-rep maximum as high-intensity, while 70% 1-rep maximum is widely accepted as high-intensity because that is the threshold where neuromuscular adaptations occur. It is possible that the RT programs did not use a high enough intensity for a neuromuscular response to occur.
  • Periodization: Kell et al. (11) enrolled CLBP patients in either a 16-week full body periodized RT program, with an exercise intensity of 53-72% of 1-rep maximum, or a periodized aerobic training program. The periodized RT program participants reported reduced pain scores and higher quality of life scores.
Chronic Tendinopathy:
Chronic tendinopathy is a common injury for both recreational and elite athletes, particularly for those involved in frequent running and jumping. The majority of RT program research has investigated the use of eccentric exercises to reduce pain and improve quality of life. With chronic Achilles tendinopathy, eccentric RT is associated with reduced pain and immediately improved function (12). Eccentric-only modalities appear to produce superior results to concentric-only and concentric-eccentric RT programs, however the methodology of several eccentric-only studies has been recently criticized, thus a specific treatment program has not yet been documented. It is unclear whether the eccentric-only rehabilitation can be classified as RT programs because the level of intensity is measured below what is required for neuromuscular adaptations.

RT programs have been used with patellar tendinopathy rehabilitation, however the literature is not extensive and the results are inconsistent with regards to eccentric-only RT. Even less data exists on the effects of eccentric-concentric RT programs for patellar tendinopathy rehabilitation. Two recent studies by Kongsgaard (13, 14) indicate that participation in a heavy RT program may be more beneficial than eccentric-only and low-intensity RT programs.

Knee Osteoarthritis:
Knee osteoarthritis is a degenerative condition that mainly affects middle-age and older populations. Other risk factors include obesity and previous sports-related knee injuries. Participants in RT programs reported decreased pain and improved functional ability. Gur et al. (15) used an isokinetic RT program with significant improvements in muscular strength and functional ability. However, better results were seen from RT programs with combined eccentric-concentric RT (15). The authors did not find conclusive evidence recommending what exercise intensity is best for knee osteoarthritis RT.

Rehabilitation After ACL Reconstruction:
RT is routinely recommended following ACL reconstruction, particularly because of quadriceps strength loss and decreased joint range of motion. Gerber et al. (16) report that an eccentric-only RT program results in greater strength gains, increased daily activity level, and quadriceps muscle hypertrophy compared to a standard RT program. However, the authors did not describe the intensity level, thus it is not possible to determine whether the eccentric-only RT program offers additional benefits over standard RT programs.

Rehabilitation After Hip Replacement Surgery:
Hip osteoarthritis is a degenerative condition that mainly affects older populations and oftentimes leads to hip replacement surgery. Suetta et al. (17) report that participation in a RT program post-surgery can increase maximal strength in 4-5 weeks and other functional parameters such as walking speed, stair climbing and seated-to-standing time. In the same study, RT decreased length of hospital stay and prevented post-surgery muscle atrophy (17). The exercise intensity started at 65% 1-rep maximum and increased to 80% 1-rep maximum. Another study by Suetta et al. (18) found that RT resulted in significant increases in muscle rate of force development (RFD). This finding is potentially linked to evidence suggesting older hip replacement patients experience greater increases in fast-twitch type II muscle fibers in response to RT. This is an important finding because it may help older people prevent falls post-surgery (18).

EDITOR’S NOTE: It reflects the overall state of the literature, but no mention was made or PRE-habilitation, or attempting to increase strength, coordination etc. to the best of our ability BEFORE a surgical procedure is undertaken. Perhaps a great topic for a future review, we shouldn’t discount the potential benefits of including this as part of a peri-surgical intervention for our patients, regardless of the surgery they are scheduled to have. Keep your patients strong and moving, to the best of your ability and your patients’ tolerance – this will make the post-surgical journey MUCH easier!

Clinical Application & Conclusions:

Based on the existing literature, the authors conclude that RT is useful for musculoskeletal rehabilitation, particularly with loss of muscular strength and functional ability. RT for chronic low back pain, knee osteoarthritis and patellar tendinopathy is beneficial. RT post-surgery is variable. For example, RT of high enough intensity to elicit neuromuscular adaptation following ACL reconstruction surgery does not seem feasible without stressing the knee joint. Yet, high-intensity RT following hip replacement surgery is feasible because the exercises target the knee joint and quadriceps instead of the hip joint. Further research is required to determine if a RT program could be developed to engage neuromuscular adaption post-ACL reconstruction.

The authors found that RT benefits are seen in both young and older populations. Younger patients will likely respond better to treatment, however RT is still an appropriate modality for older individuals.

Exercise intensity was discussed frequently in the review because the general consensus is that intensity should be decreased in a rehabilitation context to lessen the chance of re-injury. However, recent studies that used high-intensity protocols (70% 1-rep maximum) reported that the RT program is well tolerated by participants and decreases symptoms (10, 16, 17). A key concept to implement may be using periodized RT programs. Periodization is effective in healthy populations and appears to be effective with rehabilitation RT programs. Periodized programs allow participants to gradually increase maximal strength and thus increase the intensity. This approach can result in improved muscular strength and functional ability, and a reduction of symptoms (10, 16, 17). The authors conclude by stating that optimal RT programs may include protocols similar to those designed for healthy populations, despite concerns by many rehabilitation professionals.

Study Methods:

Study design is a systematic review. The authors searched the following databases: PUBMED, MEDLINE, CINAHL, and SportsDiscus for publications.

Inclusion criteria:
  • English publications
  • Published (online or print format) prior to April 2010
  • Study intervention period lasting a minimum of 4 weeks
  • Studies must have more than 1 clinically relevant outcome measure
  • Patients in study must be suffering from clinically diagnosed musculoskeletal condition
  • Intervention must include external resistance in addition to bodyweight as part of the RT.
  • /ul> Data collected identified 1545 rehabilitation patients who had participated in structured RT rehabilitation programs. Total number of patients was comprised of the following musculoskeletal conditions – chronic low back pain (CLBP) 549, tendinopathy 299, knee osteoarthritis 189, and hip replacement surgery 75.

Study Strengths / Weaknesses:

This was a narrative literature review. The authors appropriately described their search strategy.

Additional References:

  1. Hultman G, Nordin M, Saraste H, et al. Body composition, endurance, strength, cross-secitonal area, and density of MM erector spinae in men with and without low back pain. J Spinal Discord 1993;6:114-23.
  2. Manniche C, Lundberg E, Christensen I, et al. Intensive dynamic back exercises for chronic low back pain: a clinical trial. Pain 1991;47:53-63.
  3. Risch SV, Norvell NK, Pollock ML, et al. Lumbar strengthening in chronic low back pain patients. Physiologic and psychological benefits. Spine 1993;18:232-8.
  4. Rissanen A, Kalimo Hm Alaranta H. Effect of intensive training on the isokinetic strength and structure of lumbar muscles in patients with chronic low back pain. Spine 1995; 20:333-40.
  5. Danneels LA, Vanderstraeten GG, Cambier DC, et al. Effects of three different training modalities on the cross sectional area of the lumbar multifidus muscle in patients with chronic low back pain. Br J Sports Med 2001;35:186-91.
  6. Harts CC, Helmhout PH, de Bie RA, et al. A high-intensity lumbar extensor strengthening program is little better than a low-intensity program or a waiting list control group for chronic low back pain: a randomized clinical trial. Aust J Physiother 2008;54:23-31.
  7. Helmhout PH, Harts CC, Staal JB, et al. Comparison of a high-intensity and a low-intensity lumbar extensor training program as minimal intervention treatment in low back pain: a randomized trial. Eur Spine J 2004;13:537-47.
  8. Petersen T, Larsen K, Jacobsen S. One-year follow-up comparison of the effectiveness of McKenzie treatment and strengthening training for patients with chronic low back pain: outcome and prognostic factors. Spine 2007;32:2948-56.
  9. Sertpoyraz F, Eyigor S, Karapolat H, et al. Comparison of isokinetic exercise versus standard exercise training in patients with chronic low back pain: a randomized controlled study. Clin Rehabil 2009;23:238-47.
  10. Limke JC, Rainville J, Pena E, et al. Randomized trial comparing the effects of one set vs two sets of resistance exercises for outpatients with chronic low back pain and leg pain. Eur J Phys Rehabil Med 2008;44:399-405.
  11. Kell RT, Asmundson GJ. A comparison of two forms of periodized exercise rehabilitations programs in the management of chronic nonspecific low back pain. J Strength Cond Res 2009;23:513-23.
  12. Alfredson H, Pietila T, Jonsson P, et al. Heavy-load eccentric calf muscle training on recreationally active males with chronic Achilles tendinosis. Am J Sports Med 1998;26:360-6.
  13. Kongsgaard M, Kovanen V, Aagaard P, et al. Corticosteriod injections, eccentric decline squat training and heavy slow resistance training in patellar tendinopathy. Scand J Med Sports 2009;19:790-802.
  14. Kongsgaard M, Qvortrup K, Larsen, J. Fibril morphology and tendon mechanical properties in patellar tendinopathy: effects of heavy slow resistance training. Am J Sports Med 2010;38:749-56.
  15. Gur H, Cakin N, Akova B, et al. Concentric versus combined concentric-eccentric isokinetic training: effects on functional capacity and symptoms in patients with osteoarthritis of the knee. Arch Phys Med Rehabil 2002;83:208-15.
  16. Gerber JP, Marcus PL, Dibble LE, et al. Safety, feasibility, and efficacy of negative work exercise via eccentric muscle activity following interior cruciate ligament reconstruction. J Orthop Sports Phys Ther 2007;37:10-18.
  17. Suetta C, Magnusson SP, Rosted A, et al. Resistance training in the early postoperative phase reduces hospitalization and leads to muscle hypertrophy in elderly hip surgery patients – a controlled, randomized study. J Am Geriatr Soc 2004;52:2016-22.
  18. Suetta C, Aagaard P, Rosted A, et al. Training-induced changes in muscle CSA, muscle strength, EMG, and rate of force development in elderly subjects after long-term unilateral disuse. J Appl Physiol 2004;97:1954-61.