Eccentric-based training (ECC) is commonly implemented with athletes for the purposes of improvements in sport performance, injury prevention, and rehabilitation (16). Strength, hypertrophy and power are particularly targeted by practitioners (16). An eccentric muscle contraction is defined by the lengthening of skeletal muscle (13) and ECC, which may also include a concentric phase, emphasises the lengthening of the muscle-tendon unit (16). Compared to concentric-only or traditional resistance training (TRT), ECC is not constrained by concentric strength (6).
ECC, which includes training methods implemented at different loads and velocities (6,11,34), is characterised by unique physiological adaptations (6,8,9). A better understanding of these training variables and of the resulting adaptations should provide practitioners with greater confidence in selecting training methods targeting specific physiological adaptations and transfer to performance. This review focusses on chronic adaptations, excluding post-activation potentiation and other acute or short-term responses. Four combinations of load and velocity (Figure 1) are reviewed. For the purpose of this review, high load is considered as a load that exceeds maximal concentric strength and high velocity is defined by a movement where the duration of the eccentric phase is not voluntarily increased by the athlete. For each combination, training methods are identified (Table 1), physiological adaptations and changes in performance (i.e., strength or power) are reviewed, and practical applications are discussed.
High load – High velocity
Supramaximal (i.e., >concentric 1RM) accentuated eccentric loading (AEL) combines high load and high velocity. AEL is characterised by greater loading in the eccentric phase than in the concentric phase, with minimal interference to natural mechanics of movements that require coupled eccentric-concentric phases (38). It is most commonly implemented with the use of weight releasers in exercises such as the squat and the bench press (34).
Compared with TRT, supramaximal AEL appears to result in greater improvements in maximal strength, power and work capacity (3,10,38,39) and in similar changes in muscle size (3,10,30,38,39). The changes in performance have been attributed to morphological and neural factors, with an increase in fascicle length, in type IIx fibre area and in voluntary muscle activation (10,34,39,40). No changes in pennation angle or patellar tendon stiffness were reported in trained men (40). However, a lack of uniformity in research does not allow for clear conclusions on the mechanisms of change in performance and physiological adaptations following supramaximal AEL.
An eccentric load that corresponds to 100-120% concentric 1RM (CON-1RM) is suggested and the difference between the eccentric and concentric load should be >30% (35). The use of AEL on only the first repetition of a set has been shown to have a potentiating effect on following repetitions (17,37), however the chronic impact of this strategy has not been studied yet. In order to optimise adaptations, a longer training intervention (e.g., 10 weeks) may be necessary (38,39). A greater rate of perceived exertion (RPE) has been reported with AEL compared to TRT (41), training frequency should therefore be limited with an inter-session recovery of at least 48h (1). Finally, as an advanced training method, supramaximal AEL is not advised to athletes with low training age.
High load – Low velocity
Supramaximal eccentric-only training (SME) should by definition be performed without a concentric phase and with loads that exceed CON-1RM. Spotters are therefore required when an external load is used. For most athletes, the Nordic hamstring exercise (NHE), executed loaded or unloaded and which does not require external assistance, also fits into the SME category. The rationale for SME is to use the maximal mechanical tension that a muscle group can produce, resulting in greater exercise induced muscle damage (EIMD) and morphological adaptations (4).
Since isokinetic dynamometry is widely used in research (26), training and testing methods must be considered when summarising adaptations and changes in performance post-SME with the purpose of application in standard training (4). Including isokinetic methods, SME is superior to TRT to increase eccentric strength, total strength (26) and hypertrophy, particularly in fast-twitch type II fibres (28). Improvements have also been reported in elite gymnasts who improved maximal strength after four weeks of isokinetic ECC at 0.1m/s (27). Improvements were greater in eccentric than concentric strength. However, adaptations superior to TRT appear more difficult to obtain with standard weight room equipment (4). Finally, NHE training results in increased knee flexor strength and biceps femoris long head (BFlh) fascicle length, particularly when an external load is added (24,25). The change in fascicle length occurs in the distal portion of the BFlh through an increase in sarcomere length (24) and a decay in fascicle length adaptation is observed after one week only (25).
SME should only be implemented with stronger athletes who respond better to SME (4). Furthermore, SME could be dangerous for unexperienced lifters, particularly with compound exercises. Practically, loads between 105-130% CON-1RM should be used for a low number of repetitions (18,28). An eccentric duration of 2-4s is suggested to limit soreness, optimise hypertrophy and limit negative effects on explosive performance (19,28).
Low load – High velocity
The application of flywheel inertial training (FIT) has recently increased in research (22,23,36) and in team sports (15). In FIT eccentric output depends on the wheel size, force output during the concentric phase, and deceleration strategy (i.e., fast or slow) during the eccentric phase (34). Training intensity is therefore difficult to determine. This is reflected in research where inertial load is often prescribed arbitrarily (34). FIT appears effective at improving strength, power and hypertrophy, however its superiority compared to TRT in multi-joint movements and its effectiveness with well-trained athletes are still unclear (22,34,36).
Stasinaki et al. (33) compared the effect of fast <1-s (70% CON-1RM) and slow 4-s (90% CON-1RM) eccentric-only half-squats. They reported a greater increase in squat 1RM, isometric rate of force development (RFD) and vastus lateralis fascicle length in the fast group. After two weekly sessions for five weeks of fast eccentric half-squats with moderately trained females, increases in strength and power were similar with different training volumes (4x8, 6x8, 8x8), but vastus lateralis fascicle length increased and pennation angle decreased only in 6x8 and 8x8 groups. No changes in muscle fibre type composition were reported (42). Submaximal fast eccentric half-squats are therefore an effective method to develop strength and power and 64 weekly repetitions are sufficient to obtain positive adaptations.
Following the AEL overload principle, submaximal AEL, applied to ballistic exercises such as jumps and throws, may be the most advanced and effective method of this category. AEL countermovement jumps (CMJ) increased jump height, peak power and peak velocity in the CMJ in highly trained athletes more than traditional CMJ training (31). Increased neural stimulation has been suggested as the mechanism of improvement (31). AEL increases eccentric RFD and impulse (34). As a result, the muscle-tendon unit may also become more efficient at returning stored energy (31,35). Loads from 10% to 50% body mass appear effective for a vertical jump (31,35). However, more research is needed to provide clear training guidelines.
Low load – Low velocity
Submaximal tempo eccentric training (TEMPO) is characterised by coupled eccentric-concentric movements where the eccentric phase is performed at a pre-determined tempo with loads below CON-1RM (11). The rationale for the use of TEMPO is to overload the eccentric muscle action through an increased duration of the eccentric phase and therefore greater muscle activation and time under tension with the purpose of having a positive adaptation in hypertrophy or strength (34). However, the combination of submaximal load and low velocity elicits a lower eccentric peak force (34), likely limiting a positive transfer to performance.
A meta-analysis by Schoenfeld et al. (29) showed that TEMPO is not superior to shorter repetition durations when targeting hypertrophy. Greater improvements in CON-1RM have also been reported with a 2-s eccentric phase than with a 4-s phase (12,32) and a 6-s eccentric resulted in decreased CMJ performance (19).
TEMPO does not appear to provide benefits for hypertrophy and strength. TEMPO is also characterised by a greater RPE (5). Practitioners should therefore consider carefully whether TEMPO can provide desired adaptations. TEMPO provides time under tension, which may be used when other methods are not be applicable. With an extended duration, loads and repetitions may not be compared with TRT loading and lighter loads are required to complete a similar number of repetitions.
Practical considerations
When implementing ECC, practitioners should consider EIMD, delayed onset muscle soreness (DOMS) and the repeated-bout effect (RBE). Greater external load and range of motion result in greater EIMD (7,21). Velocity however does not appear to be a main factor for EIMD (20). Submaximal ECC results in lower DOMS than maximal ECC (21), favouring athlete availability to subsequent training. Finally, the RBE is a protective effect against muscle damage that results from a single bout of ECC (14,21), acting therefore as a soft-tissue injury prevention mechanism. It is therefore recommended to start integrating ECC in the general preparation phase with a progressive increase in volume and intensity.
Conclusion
The conclusions of this brief review are limited by the restricted number of training methods and variables that could be considered and by the still scarce research on methods such as AEL. Still, based on the adaptations presented above and their effect on athletic performance, this review highlights the importance to consider load and velocity when implementing ECC and offers an overview of physiological adaptations that may be targeted by practitioners with eccentric-based training.
References
1. Bartolomei, S., Totti, V., Nigro, F., Ciacci, S., Semprini, G., Michele, R. D., Cortesi, M., & Hoffman, J. R. (2019). A comparison between the recovery responses following an eccentrically loaded bench press protocol vs. regular loading in highly trained men. Journal of Human Kinetics, 68, 59–67.
2. Bigland-Ritchie, B., & Woods, J. J. (1976). Integrated electromyogram and oxygen uptake during positive and negative work. Journal of Physiology, 260(2), 267–277.
3. Brandenburg, J. P., & Docherty, D. (2002). The effects of accentuated eccentric loading on strength, muscle hypertrophy, and neural adaptations in trained individuals. Journal of Strength and Conditioning Research, 16(1), 25–32.
4. Buskard, A. N. L., Gregg, H. R., & Ahn, S. (2018). Supramaximal eccentrics versus traditional loading in improving lower-body 1RM: A meta-analysis. Research Quarterly for Exercise and Sport, 89(3), 340–346.
5. Diniz, R. C. R., Martins-Costa, H. C., Machado, S. C., Lima, F. V., & Chagas, M. H. (2014). Repetition duration influences ratings of perceived exertion. Perceptual and Motor Skills, 118(1), 261-273E.
6. Douglas, J., Pearson, S., Ross, A., & McGuigan, M. (2017). Chronic adaptations to eccentric training: A systematic review. Sports Medicine, 47(5), 917–941.
7. Fochi, A. G., Damas, F., Berton, R., Alvarez, I., Miquelini, M., Salvini, T. F., & Libardi, C. A. (2016). Greater eccentric exercise-induced muscle damage by large versus small range of motion with the same end-point. Biology of Sport, 33(3), 285–289.
8. Franchi, M. V., Atherton, P. J., Reeves, N. D., Flück, M., Williams, J., Mitchell, W. K., Selby, A., Beltran Valls, R. M., & Narici, M. V. (2014). Architectural, functional and molecular responses to concentric and eccentric loading in human skeletal muscle. Acta Physiologica, 210(3), 642–654.
9. Franchi, M. V., Reeves, N. D., & Narici, M. V. (2017). Skeletal muscle remodeling in response to eccentric vs. concentric loading: Morphological, molecular, and metabolic adaptations. Frontiers in Physiology, 8:447.
10. Friedmann-Bette, B., Bauer, T., Kinscherf, R., Vorwald, S., Klute, K., Bischoff, D., Müller, H., Weber, M.-A., Metz, J., Kauczor, H.-U., Bärtsch, P., & Billeter, R. (2010). Effects of strength training with eccentric overload on muscle adaptation in male athletes. European Journal of Applied Physiology, 108(4), 821–836.
11. Harden, M., Bruce, C., Wolf, A., Hicks, K. M., & Howatson, G. (2020). Exploring the practical knowledge of eccentric resistance training in high-performance strength and conditioning practitioners. International Journal of Sports Science & Coaching, 15(1), 41–52.
12. Headley, S. A., Henry, K., Nindl, B. C., Thompson, B. A., Kraemer, W. J., & Jones, M. T. (2011). Effects of lifting tempo on one repetition maximum and hormonal responses to a bench press protocol. Journal of Strength and Conditioning Research, 25(2), 406–413.
13. Lindstedt, S. L., LaStayo, P. C., & Reich, T. E. (2001). When active muscles lengthen: Properties and consequences of eccentric contractions. Physiology, 16(6), 256–261.
14. McHugh, M. P. (2003). Recent advances in the understanding of the repeated bout effect: The protective effect against muscle damage from a single bout of eccentric exercise. Scandinavian Journal of Medicine & Science in Sports, 13(2), 88–97.
15. McNeill, C., Beaven, C. M., McMaster, D. T., & Gill, N. (2019). Eccentric training interventions and team sport athletes. Journal of Functional Morphology and Kinesiology, 4(4), 67.
16. McNeill, C., Beaven, C. M., McMaster, D. T., & Gill, N. (2020). Survey of eccentric-based strength and conditioning practices in sport. Journal of Strength and Conditioning Research, 34(10), 2769–2775.
17. Merrigan, J. J., Tufano, J. J., Falzone, M., & Jones, M. T. (2020). Effectiveness of accentuated eccentric loading: Contingent on concentric load. International Journal of Sports Physiology and Performance, 16(1), 66–72.
18. Mike, J., Kerksick, C. M., & Kravitz, L. (2015). How to incorporate eccentric training into a resistance training program. Strength and Conditioning Journal, 37(1), 5–17.
19. Mike, J. N., Cole, N., Herrera, C., VanDusseldorp, T., Kravitz, L., & Kerksick, C. M. (2017). The effects of eccentric contraction duration on muscle strength, power production, vertical jump, and soreness. Journal of Strength and Conditioning Research, 31(3), 773–786.
20. Nogueira, F. R. D., Conceição, M. S., Vechin, F. C., Junior, E. M. M., Rodrigues, G. F. C., Fazolin, M. A., Chacon-Mikahil, M. P. T., & Libardi, C. A. (2013). The effect of eccentric contraction velocity on muscle damage: A review. Isokinetics and Exercise Science, 21(1), 1–9.
21. Nosaka, K., & Newton, M. (2002). Difference in the magnitude of muscle damage between maximal and submaximal eccentric loading. Journal of Strength and Conditioning Research, 16(2), 202–208.
22. Nuñez Sanchez, F. J., & Sáez de Villarreal, E. (2017). Does flywheel paradigm training improve muscle volume and force? A meta-analysis. Journal of Strength and Conditioning Research, 31(11), 3177–3186.
23. Petré, H., Wernstål, F., & Mattsson, C. M. (2018). Effects of flywheel training on strength-related variables: A meta-analysis. Sports Medicine - Open, 4(1), 55.
24. Pincheira, P. A., Boswell, M. A., Franchi, M. V., Delp, S. L., & Lichtwark, G. A. (2021). Biceps femoris long head sarcomere and fascicle length adaptations after three weeks of eccentric exercise training. bioRxiv. https://www.biorxiv.org/content/10.1101/2021.01.18.427202v1
25. Pollard, C. W., Opar, D. A., Williams, M. D., Bourne, M. N., & Timmins, R. G. (2019). Razor hamstring curl and Nordic hamstring exercise architectural adaptations: Impact of exercise selection and intensity. Scandinavian Journal of Medicine & Science in Sports, 29(5), 706–715.
26. Roig, M., O’Brien, K., Kirk, G., Murray, R., McKinnon, P., Shadgan, B., & Reid, W. D. (2009). The effects of eccentric versus concentric resistance training on muscle strength and mass in healthy adults: A systematic review with meta-analysis. British Journal of Sports Medicine, 43(8), 556–568.
27. Schärer, C., Tacchelli, L., Göpfert, B., Gross, M., Lüthy, F., Taube, W., & Hübner, K. (2019). Specific eccentric–isokinetic cluster training improves static strength elements on rings for elite gymnasts. International Journal of Environmental Research and Public Health, 16(22), 4571.
28. Schoenfeld, B. (2011). The use of specialized training techniques to maximize muscle hypertrophy. Strength and Conditioning Journal, 33(4), 60–65.
29. Schoenfeld, B. J., Ogborn, D. I., & Krieger, J. W. (2015). Effect of repetition duration during resistance training on muscle hypertrophy: A systematic review and meta-analysis. Sports Medicine, 45(4), 577–585.
30. Schoenfeld, B. J., & Grgic, J. (2018). Eccentric overload training: A viable strategy to enhance muscle hypertrophy? Strength and Conditioning Journal, 40(2), 78–81.
31. Sheppard, J., Hobson, S., Barker, M., Taylor, K., Chapman, D., McGuigan, M., & Newton, R. (2008). The effect of training with accentuated eccentric load counter-movement jumps on strength and power characteristics of high-performance volleyball players. International Journal of Sports Science & Coaching, 3(3), 355–363.
32. Shibata, K., Takizawa, K., Nosaka, K., & Mizuno, M. (2021). Effects of prolonging eccentric phase duration in parallel back-squat training to momentary failure on muscle cross-sectional area, squat one repetition maximum, and performance tests in university soccer players. Journal of Strength and Conditioning Research, 35(3), 668–674.
33. Stasinaki, A.-N., Zaras, N., Methenitis, S., Bogdanis, G., & Terzis, G. (2019). Rate of force development and muscle architecture after fast and slow velocity eccentric training. Sports, 7(2), 41.
34. Suchomel, T. J., Wagle, J. P., Douglas, J., Taber, C. B., Harden, M., Haff, G. G., & Stone, M. H. (2019). Implementing eccentric resistance training — Part 1: A brief review of existing methods. Journal of Functional Morphology and Kinesiology, 4(2), 38.
35. Suchomel, T. J., Wagle, J. P., Douglas, J., Taber, C. B., Harden, M., Haff, G. G., & Stone, M. H. (2019). Implementing eccentric resistance training — Part 2: Practical recommendations. Journal of Functional Morphology and Kinesiology, 4(3), 55.
36. Vicens-Bordas, J., Esteve, E., Fort-Vanmeerhaeghe, A., Bandholm, T., & Thorborg, K. (2018). Is inertial flywheel resistance training superior to gravity-dependent resistance training in improving muscle strength? A systematic review with meta-analyses. Journal of Science and Medicine in Sport, 21(1), 75–83.
37. Wagle, J. P., Cunanan, A. J., Carroll, K. M., Sams, M. L., Wetmore, A., Bingham, G. E., Taber, C. B., DeWeese, B. H., Sato, K., Stuart, C. A., & Stone, M. H. (2021). Accentuated eccentric loading and cluster set configurations in the back squat: A kinetic and kinematic analysis. Journal of Strength and Conditioning Research, 35(2), 420–427.
38. Wagle, J. P., Taber, C. B., Cunanan, A. J., Bingham, G. E., Carroll, K. M., DeWeese, B. H., Sato, K., & Stone, M. H. (2017). Accentuated eccentric loading for training and performance: A review. Sports Medicine, 47(12), 2473–2495.
39. Walker, S., Blazevich, A. J., Haff, G. G., Tufano, J. J., Newton, R. U., & Häkkinen, K. (2016). Greater strength gains after training with accentuated eccentric than traditional isoinertial loads in already strength-trained men. Frontiers in Physiology, 7:149.
40. Walker, S., Trezise, J., Haff, G. G., Newton, R. U., Häkkinen, K., & Blazevich, A. J. (2020). Increased fascicle length but not patellar tendon stiffness after accentuated eccentric-load strength training in already-trained men. European Journal of Applied Physiology, 120(11), 2371–2382.
41. Yarrow, J. F., Borsa, P. A., Borst, S. E., Sitren, H. S., Stevens, B. R., & White, L. J. (2007). Neuroendocrine responses to an acute bout of eccentric-enhanced resistance exercise. Medicine & Science in Sports & Exercise, 39(6), 941–947.
42. Zacharia, E., Spiliopoulou, P., Methenitis, S., Stasinaki, A.-N., Zaras, N., Papadopoulos, C., Papadimas, G., Karampatsos, G., Bogdanis, G. C., & Terzis, G. (2019). Changes in muscle power and muscle morphology with different volumes of fast eccentric half-squats. Sports, 7(7), 164.