Muscle fibre & strength gains
This will take you 5-6 minutes to read.
Muscle tissues exist in a dynamic state where proteins are alternately synthesised with a net deposition of amino acids and degraded with a net release of amino acids. Genetic factors provide the different factors that increase muscle mass and strength. Muscular activity contributes little to tissue growth without appropriate nutrition, particularly amino acid availability (protein), to provide essential building blocks. Similarly, specific hormones (e.g., testosterone, growth hormone, соrtisol, and, most importantly, insulin and systemic and local insulin like growth factors), including neural system innervation, help to pattern and reinforce the appropriate training adaptation.
When gaining muscle size and strength, focussing on mechanical tension, appropriate nutrition strategies, increased sleep quality and sufficient rest between sets and sessions, will enhance your adaptation response. Without mechanical tension and tension overload, each of the other factors cannot effectively produce the desired training response.
The progressive resistance exercise (PRE) training method provides a practical application of the overload principle and forms the basis of most resistance-training programs. Physical therapists in a rehabilitation hospital in the late 1940s and early 1950s programmed weight-training regimens to improve the strength of previously injured limbs of soldiers returning from World War 2.
Different variations of progressive resistance exercise exist. I am going to set out 14 general findings from research studies on the optimal number of sets and repetitions, including frequency and relative intensity of progressive resistance exercise for optimal strength improvements:
1. Most Personal Trainer qualifications have sort of got this first point relatively correct. Eight to 12 repetitions max (RM) proves effective in novice training, whereas 1-12 RM effectively loads for intermediate training. This can then increase to more intense loading using 1-6 RM. We need to be loading the muscle with as much mechanical tension, so the muscle fails the task as opposed to changing acidity of muscle, implications of poor cardiovascular endurance and other potential limiting physiological factors.
2. Rest for 3 minutes between sets of an exercise at moderate movement velocity (1 to 2 s concentric; 1 to 2s eccentric or even better, depending on your training experience 2 to 8 seconds spread over the concentric and eccentric phase). Always try to focus on stretch-mediated hypertrophy but partial repetitions do have their place regarding strength gains.
3. For PRE at a specific RM load, increase load 2 to 10% when the individual performs one to two repetitions above the current workload.
4. Performing one exercise set induces only slightly less strength improvement in recreational weightlifters than performing two or three sets. For those who desire to maximize muscle strength and size gains, higher volume, multiple-set paradigms emphasising 6- to 12-RM at moderate velocity with 2- to 3-min rests between sets would seem to prove most effective.
5. Single-set programs generally produce most of the health and fitness benefits of multiple-set programs. These "lower-volume" programs also produce greater compliance and reduce time commitment. Saying this, always remember, just because you can, does that mean you should? I would personally recommend 10-18 sets per muscle group to have noticeable hypertrophy gains.
6. Novices and intermediates should train at least 2 to 3 days a week, whereas the advanced can train 3 to 4 days a week. Such a generalisation is not without a potential downside. High training frequency extends the transient activation of inflammatory signalling cascades, associated with persistent suppression of key mediators of anabolic responses, which could blunt training responses. Inflammation is great for adaptation but if you do not give yourself sufficient recovery, you will be potentially blunting the adaptation response due to potential central nervous system (CNS) mediated fatigue or potential muscle damage. Make sure your nutrition and sleep are prioritised.
7. Training twice every second day produces overall superior results compared with daily training. This may occur from the effects of low muscle glycogen content (with training twice every second day) on enhanced transcription of genes involved in training adaptations.
8. If training includes multiple exercises, 4 or 5 days per week may produce less improvement than training two or three times a week because near-daily training of the same muscles impairs muscle recuperation between training sessions. In adequate recovery reduces progress in neuromuscular and structural adaptations and strength development.
9.A fast rate of moving a given resistance generates more strength improvement than moving at a slower rate. There is no inherent superiority for developing muscle strength gains in free weights (barbells, weight plates, dumbbells) vs machines.
10. Exercise should sequence to optimise workout quality by engaging large before small muscle groups, multiple-joint exercises before single-joint exercises, and higher intensity exercise before lower-intensity exercise when doing strength gains.
11. With hypertrophy-based training on days where lower limbs are being prioritised, pre-exhaust training might be more beneficial. This contradicts point 10 due to a necessary increase in muscle fibre recruitment required with larger lifts necessary for sarcomereogensis. The intensity required to increase muscle fibre size and strength seems to be superior to other muscle groups.
12. Combined resistance-training concentric and eccentric muscle actions augment effectiveness; include both single-joint and multiple-joint exercises to potentiate a muscle's strength and fibre size.
13. Overload training that includes eccentric muscle actions preserves strength gains better during a maintenance phase than concentric-only training.
14. Power training should apply the strategy to improve muscular strength plus include lighter loads (30 to 60% of 1-RM) performed at fast contraction velocity. Use 2 to 3 to 5 minute minute rest periods between sets relieving of physiological barriers such as increased muscle acidity and cardiovascular output. Focus on multiple-joint movements that activate larger muscle groups.
Recommended readings
Staron, R. S., Malicky, E. S., Leonardi, M. J., Falkel, J. E., Hagerman, F. C., & Dudley, G. A. (1990). Muscle hypertrophy and fast fiber type conversions in heavy resistance-trained women. European Journal of Applied Physiology and Occupational Physiology, 60, 71-79.
Ahtiainen, J. P., Pakarinen, A., Alen, M., Kraemer, W. J., & Häkkinen, K. (2003). Muscle hypertrophy, hormonal adaptations and strength development during strength training in strength-trained and untrained men. European Journal of Applied Physiology, 89, 555-563.
Delextrat, A. et al. (2020). Changes in torque-angle profiles of the hamstrings and hamstrings-to-quadriceps ratio after two hamstring strengthening exercise interventions in female hockey players. The Journal of Strength & Conditioning Research, 34(2), 396-405.
Fry, A. C. (2004). The role of resistance exercise intensity on muscle fibre adaptations. Sports medicine, 34, 663-679.
Stewart, J. C., Saba, A., Baird, J. F., Kolar, M. B., O' Donnell, M., & Schaefer, S. Y. (2021). Effect of standing on a standardized measure of upper extremity function. OTJR: Occupation, Participation and Health, 41(1), 32-39.
Senna, G. W., Dantas, E. H. M., Scudese, E., Brandão, P. P., Lira, V. A., Baffi, M., & Bianco, A. (2022). Higher muscle damage triggered by shorter inter-set rest periods in volume-equated resistance. Strength & Conditioning exercise. Frontiers in Physiology, 225.