Strength training as medicine? - Mind before Matter!

Strength training as medicine? - Mind before Matter

Muscle strength, as the basis for movement, is the ability of a muscle to overcome (concentric), hold back (eccentric), or maintain (static) a resistance through a contraction. Because muscles control all possible movements, it is obvious that greater muscle strength leads to better and faster movements. In top-level sports, mechanical power (product of force and speed) is more often referred to as the decisive performance component in strength applications. Since force inputs initiate movements, the relationship between force and speed is important in all sports (Lehmann et al. 2019) but also within rehabilitation because of the lower joint load. For this reason, strength training is an important part of sports training and rehabilitation of back and joint problems.

Physiologically, muscle strengthening means no more and no less than, on the one hand, more motor units are activated; on the other, these muscle fibers can contract further. And this is a neurological phenomenon controlled by the brain. The more control potential can be activated in the brain, the more intensely the muscle contracts. The prerequisite for this is that the exact function of the muscle in terms of a movement is well understood by the athlete or patient so that this movement is performed optimally and as cleanly as possible. A graphic representation of this movement and manual (resistive) guidance can be very helpful here.

Strengthening muscles is thus both physically and mentally intensive and bases very precise motor learning.

Studies on trunk muscle strength are mostly limited to maximal isometric strength and endurance. Studies evaluating the effects of trunk muscle training on strength and speed (e.g. deadlift, high pull, or woodchopper exercise) are only sporadic (Zemková 2022). 

The main elements of strength training or powerlifting are squat, bench press, and deadlift lifting a weight of up to 4x bodyweight and bodyweight exercises. Of these, the (back) squat (sitting/standing as a basic movement) is the most common and fundamental exercise for lower extremity strength and conditioning within sport (Glassbrook et al. 2017) and is widely regarded as a valid and reliable measure of leg and trunk strength and function (Comfort et al. 2014, Sleivert et al. 2004, Wisløff et al. 2004). Moreover, the squat is an effective mechanism in rehabilitation after knee injuries (Myer et al. 2004, Heijne et al. 2004). The major benefits of the squat are due to the contributions of the quadriceps, hamstrings, gluteus, erector, and triceps surae muscle groups to complete the movement (Maddigan et al. 2014, 2 Robertson et al. 2008). 
Other researchers also show that powerlifting and bodyweight exercises can be used meaningfully in the rehabilitation of back pain, among others. Behavioral measures remain important in this regard (Gibbs et al. 2022). Krueger et al. 2020 describe a case study where power training is more effective than eccentric training in a hamstring injury. Powerlifting has a beneficial effect on back pain although a clear relationship between increased strength and endurance of the trunk muscles and less back pain remains unclear (Zemková & Zapletalová 2021).

At the same time, lower back pain (LBP) is a common problem in powerlifters although its role in the development of lower back pain is not entirely clear. Overloading of the lumbar back, improper lifting technique, too few breaks, large range of motion, and stiff hip joints may play a role.
Strömbäck et al (2018): 70% are currently injured, with 87% having sustained an injury in the past 12 months with the lumbar pelvic area, shoulder, and hip being the most affected in particular. The neck and chest were more affected in females. 16% of those injured had to stop training.
Siewe et al (2011): 43.3% of weightlifters have complaints (shoulder, back, and knee) during training but these are not a reason to stop training.
Keogh et al. (2006): 39% of complaints involve the shoulder, 24% lower back, 11% elbow, and 9% knee. In addition, 22-32% squat related, 18-46% benchpress related, and 12-31% deadlift related.
Bengtsson et al (2018) describe squat-related injuries as bilateral patellar tendon ruptures, tibia, and fibula spiral fracture, partial anterior cruciate ligament rupture involving the use of anabolic steroids, (partial) tearing of the rectus femoris head with a labrum tear, tearing of the proximal tendon of the biceps femoris and talus dome leasia (impression fracture) and a Clay-shoveler's (cerv. proc. spin) fracture.

Among bench press-related injuries are the frequently occurring pect major rupture, triceps tendon rupture (correlated with anabolic stereoid use and chronic elbow pain and triceps tendinitis), osteololysis of the distal clavicle (weightlifter's shoulder), and tendinopathy of the pect minor (bench presser's shoulder) and anterior and posterior shoulder luxations. Also mentioned were clavicula, scaphoid, second rib fracture, and Salter-Harris type I fracture of the distal radius.
Deadlift-related injuries involve the lower back, hip (acetabulum stress fracture), pectoralis major rupture, hamstring ruptures, avulsion of the SIAS, meniscus rupture, and lumbosacral injury (SIG).
Also, the specific form of strength training CrossFit, which combines high-intensity interval training with fitness training and consists of functional movements from everyday life, such as squatting, pulling, pushing, etc., leads to similar injuries as powerlifting with the most affected areas being the shoulders, spine, and knee (Rodríguez et al. 2022). The injury prevalence is 73.5% (Hak et al. 2013).

Strength and mobility
Well-dosed and correctly performed strength training using the strength torques always leads to improvement in mobility. A carefully constructed full-range resistance program can improve flexibility as much as the typical muscle stretching programs used in many fitness programs (Morton et al. 2011). 
In powerlifting, mobility can decrease without pain symptoms, indicating, that the training (technique and intensity) can be improved. 
For example, powerlifting leads to significantly less flexion and horizontal abduction in the shoulder (Spence et al. 2023, Gadomski et al. (2018) and less flexion, extension, and adduction in the hip than recreationally trained men (Spence et al. 2023). Cutrufello et al. (2017) found significant shortening of the Pectoralis minor as well as force imbalance between (horizontal) adductors (+) and abductors (-) of the shoulder flexors (-) and -extensors (+) of the knee.

Strength training as medicine?
Is there a medical need for exercise for back and joint complaints?
There is general consensus on the positive effects of exercise for musculoskeletal complaints, both within the world of fitness and sport and within the medical profession. But even strength training cannot convince as a best practice training form to permanently reduce musculoskeletal complaints.
Certain forms and/or intensity of strength training can also lead to other, sometimes severe complaints. Also, existing (back and joint) complaints can worsen when starting strength training thoughtlessly.
Correctly dosed and correctly performed strength training always takes into account the load capacity of joints. To this end, knowledge of the biomechanical and neuromuscular properties of joints, i.e. the relationship between joint functions and locomotion, is indispensable.
To properly assess whether and to what extent strength training should be considered in the treatment of back and joint pain, an examination of joint and muscle functions is needed. Particularly important here is the functioning of the force couple around a joint. Strength training should then aim to restore the balance within the force couple and improve the function of the entire force couple. This is what the PhysioNovo concept focuses on.
For back, shoulder, and hip complaints, the force couples of the shoulder and hip are most important. The muscles involved are the largest and strongest in the entire body.
Strength training that focuses on strength couples and takes into account the load capacity of joints leads to a reduction in back and joint pain and is a medical necessity. Because only correctly performed and correctly dosed strength training can improve the functions of diseased joints via muscle activation and sustainably reduce the associated complaints.
Even in healthy joints or joints with motor deficits but no pain symptoms yet, this correct strength training is particularly important from a preventive point of view.

It can be said that strength training that meets these conditions can be considered medicine.

© Paul Geraedts, June 2023.

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