Lauritzen, F., Paulsen, G., Raastad, T., Bergersen, L. H., and Owe, S. G. (2009). Severe ultrastructural changes and necrotic fiber segments in the flexor muscles of the elbow after a maximum voluntary eccentric effect in humans. J. Appl. Physiol. 107, 1923–1934.
doi: 10.1152/japplphysiol.00148.2009 A condition that occurs when the tendon and surrounding tissues become inflamed and irritated. This is usually due to overuse, especially jumping activities. This is the reason why chronic patellar tendonitis is often referred to as the “jumping knee”. A study by Roald Bahr and colleagues examined which method of tendon rehabilitation exercise — the “eccentric squat” or the universal “leg extension/leg loop” exercise — provided more recovery results in terms of recovery in the treatment of chronic patellar tendonitis. During the twelve-week training program, participants were tested for thigh and quadriceps circumference and thigh strength moment. There was no significant difference between the quadriceps groups or the moment of thigh strength and the thigh moment, which increased significantly in both groups, but the eccentric squat saw significantly lower pain scores and produced twice as many “painless” subjects as the other group at the end of the program.  Osteopenia, which is generally considered a precursor to osteoporosis, occurs when bone density is below normal levels. Bone mass is influenced by muscle forces and their load on the bone structure. The strength and density of the bone is directly affected by the local load. Due to the high load on the muscles during eccentric training, combined with low energy production, eccentric training becomes a cornerstone of the rehabilitation process.  Peters, D., Barash, I. A., Burdi, M., Yuan, P.
S., Mathew, L., Friden, J., et al. (2003). Asynchronous functional, cellular and transcriptional changes after eccentric exercise in rats. J. Physiol. 553 (Pt 3), 947-957. Interestingly, the intensity of DOMS is lower in the elderly than in young adults. This is due to a decrease in range of motion in the elderly population and atrophy of rapidly contracting muscle fibers.
For this reason, eccentric training to improve strength is recommended for the elderly. Roig, M., Macintyre, D. L., Eng, J. J., Narici, M. V., Maganaris, C. N., and Reid, W. D. (2010).
Maintaining eccentric strength in the elderly: evidence, mechanisms and implications for exercise and rehabilitation. Exp. Gerontol. 45, 400–409. doi: 10.1016/j.exger.2010.03.008 Rattray, B., Thompson, M., Ruell, P., and Caillaud, C. (2013). Specific training improves mitochondrial calcium homeostasis of skeletal muscles after eccentric exercise. Euro. J. Appl.
Physiol. 113, 427–436. doi: 10.1007/s00421-012-2446-1 Chen, T.C., Lin, K. Y., Chen, H. L., Lin, M. J. and Nosaka, K. (2011). Comparison of muscle damage induced by eccentric stress between four muscles of the limbs. Euro. J.
Appl. Physiol. 111, 211–223. doi: 10.1007/s00421-010-1648-7 Hyldahl, R. D., and Hubal, M. J. (2014). Broadening our perspective: morphological, cellular and molecular responses to eccentric training. Muscle nerve 49, 155–170. doi: 10.1002/mus.24077 Marcus, R. L., Smith, S., Morrell, G., Addison, O., Dibble, L.
E., Wahoff-Stice, D., et al. (2008). Comparison of combined aerobic and eccentric resistance training with high strength with aerobic training only for people with type 2 diabetes mellitus. Phys. Ther. 88, 1345–1354. doi: 10.2522/ptj.20080124 Thompson, H. S., Clarkson, P.M., and Scordilis, S. P. (2002). The repeated fighting effect and heat shock proteins: intramuscular expression HSP27 and HSP70 after two eccentric workouts in humans.
Acta physiol. Scanned. 174, 47–56. A new model of muscle contraction is proposed that explains the increase in strength in eccentric muscle action, the decrease in metabolic energy and RFE. Mahieu et al. Effect of eccentric training on the properties of the tendon tissue of the plantar flexor muscle (2008) What exactly was this miraculous protocol? He focused on “the tension of the thigh muscles during prolonged lengthening, mainly during eccentric muscle actions.” All exercises were performed painlessly. The exercises were “the extender”, “the diver” and “the glider”. Videos available for free by the British Medical Journal in full text by Askling et al.
– the “additional videos” numbered 1-3. This topic is also discussed in detail in my book on muscle tension. Baumert, P., Lake, M. J., Stewart, C. E., Drust, B., and Erskine, R.M. (2016). Interindividual variability in response to the maximum eccentric load. Euro. J.
Appl. Physiol. 116, 2055–2056. It was concluded that high muscle tendon forces delivered in a controlled environment are necessary for optimal tendon fit. Although eccentric tension is related to injury, eccentric exercises with high strength are necessary to maximize recovery.  Chaabene, H., Prieske, O., Negra, Y., and Granacher, U. (2018). Directional Change Speed: Towards a strength training approach with accentuated eccentric muscle actions.
Sports Med. 48, 773–779. doi: 10.1007/s40279-018-0907-3 Yu, J. G., Malm, C., and Thornell, L. E. (2002). Eccentric contractions that lead to DOMS do not cause loss of desmin or fibrous necrosis in the human muscle. Histochem. Cellular biol. 118, 29–34. Applications of eccentric training. Eccentric contractions have the characteristics of high strength output and low metabolic needs (top row).
Its properties make it possible to load the musculoskeletal system in different ways compared to conventional concentric training, which leads to specific training advantages (middle row). These advantages are particularly suitable for various applications (bottom row). For example, the low cardiac output and perceived low exertion resulting from the low energy costs of eccentric exercise are particularly beneficial for the rehabilitation of frail elderly people or people with cardiomyopathy. According to Lindstedt et al. (2001). Friden, J., Seger, J., Sjostrom, M., and Ekblom, B. (1983a). Adaptive response in human skeletal muscles, which is subjected to prolonged eccentric training. Int. J. Sports Med. 4, 177–183.
Talbot, J. A., and Morgan, D. L. (1998). The effects of stretching parameters on damage induced by eccentric load to the toad`s skeletal muscle. J. Muscle Res. Zellmotil. 19, 237–245. Two situations can lead to an eccentric movement from this moment on; Frankenberg, N. T., Lamb, G. D., Overgaard, K., Murphy, R.M., and Vissing, K.
(2014). After eccentric training, small heat shock proteins translocate to the cytoskeleton in human skeletal muscle, regardless of phosphorylation. J. Appl. Physiol. 116, 1463–1472. doi: 10.1152/japplphysiol.01026.2013 Reeves, N. D., Maganaris, C.
N., Longo, S., and Narici, M. V. (2009). Differential adaptations to eccentric resistance training compared to conventional training in the elderly. .