2024.02.22
Dr. Shirin Davarpanah Jazi, introduces, as part two of a two-part series, the difference in skeletal muscle actions. Shirin is a highly accomplished Karate expert, holding black belts in Shotokan and Shitoryu styles, while also being the first Iranian female to achieve international officiating status in 2002. Additionally, she has a PhD in Human Neuroscience and is a physiotherapist, specializing in human movement and fitness.


Eccentric and concentric exercises are used in various situations depending on the desired benefits and limitations of each type of contraction. Here's a breakdown:

Eccentric Exercises:

• Benefits:
• Strengthening muscles: Eccentric contractions can generate greater force with reduced metabolic requirements compared to concentric ones, leading to increased muscle strength and power. (1)
• Rehabilitating injuries: Eccentric exercises are often used in rehabilitation programs because they are less stressful on tendons and joints compared to concentric contractions. Specific protocols like the Alfredson protocol for Achilles tendinitis often use eccentric exercises. (2)
• Improving balance and coordination: Eccentric contractions play a crucial role in controlling movements and maintaining balance. (3)
• Improving bone density: Studies suggest eccentric exercises can stimulate bone growth and improve bone density. (4)

Concentric Exercises:

• Benefits:
• Moving objects: Lifting weights, pushing machines, pulling objects - any action that overcomes external resistance in our daily life uses concentric contractions.
• Less muscle soreness and shorter recovery time: These exercises are used to boost training volume and muscle activation without the mechanical stress and damage associated with eccentric movements. This is why they're favored during active recovery periods. (5)
• Sports training: Concentric contractions are essential for improving performance in various sports (such as volleyball, cycling and swimming) involving jumping, throwing, and sprinting. (6)

Summary:

Both concentric (muscle shortening) and eccentric (muscle lengthening) contractions contribute to muscle growth, but with some differences:

• Muscle growth: Eccentrics have a slight edge for hypertrophy, but the difference is small. Combining both of your workouts is highly recommended.
• Soreness and recovery: Eccentrics cause more soreness, but can also lead to faster strength gains and shorter recovery times (for experienced individuals). Concentrics are good for active recovery.
• Training volume and activation: Concentrics can increase volume without excessive soreness, while eccentrics contribute through techniques like negatives. Both activate muscles effectively, with different emphasis.
• Recovery periods: Both have a place. Concentrics are preferred for low-intensity activation and managing soreness, while eccentrics can be used in specific rehab protocols.

Remember: The best approach depends on your goals, fitness level, and specific needs . Consult a qualified professional for a personalized training program utilizing both types of contractions strategically.

Key takeaway: Combining eccentric and concentric exercises maximizes muscle growth and strength gains while addressing individual requirements.

References:

1. Ansari M, Hardcastle S, Myers S, Williams AD. The Health and Functional Benefits of Eccentric versus Concentric Exercise Training: A Systematic Review and Meta-Analysis. J Sports Sci Med. 2023 Jun 1;22(2):288-309. doi: 10.52082/jssm.2023.288. PMID: 37293426; PMCID: PMC10244982.
2. Harris-Love MO, Gollie JM, Keogh JWL. Eccentric Exercise: Adaptations and Applications for Health and Performance. J Funct Morphol Kinesiol. 2021 Nov 24;6(4):96. doi: 10.3390/jfmk6040096. PMID: 34842737; PMCID: PMC8628948.
3. Isner-Horobeti ME, Dufour SP, Vautravers P, Geny B, Coudeyre E, Richard R. Eccentric exercise training: modalities, applications and perspectives. Sports Med. 2013 Jun;43(6):483-512. doi: 10.1007/s40279-013-0052-y. PMID: 23657934.
4. Singh, H., Moore, BA, Rathore, R. et al. Skeletal effects of eccentric strengthening exercise: a scoping review. BMC Musculoskeletal Disord 24 , 611 (2023). https://doi.org/10.1186/s12891-023-06739-6
5. Newham DJ, Mills KR, Quigley BM, Edwards RH. Pain and fatigue after concentric and eccentric muscle contractions. Clin Sci (Lond). 1983 Jan;64(1):55-62. doi: 10.1042/cs0640055. PMID: 6822050.
6. Córdova-Martínez A, Caballero-García A, Bello HJ, Perez-Valdecantos D, Roche E. Effects of Eccentric vs. Concentric Sports on Blood Muscular Damage Markers in Male Professional Players. Biology . 2022; 11(3):343. https://doi.org/10.3390/biology11030343