Muscle Damage Does Not Cause Growth
Strength training sessions that cause high levels of muscle soreness are probably counter-productive. Program your resistance training more intelligently.
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Damas et al. (2018). The development of skeletal muscle hypertrophy through resistance training: The role of muscle damage and muscle protein synthesis. European Journal of Applied Physiology, 118, 485-500.
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The purpose of this study was to review the role of muscular damage (think: soreness—a useful proxy) and its involvement in hypertrophy (muscular growth).
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In this study/review:
>Historically, muscular damage from resistance training, which leads to delayed onset muscle soreness (DOMS), has been thought of as a primary mechanism driving hypertrophy. This paradigm is currently being challenged.
>Muscle damage is the morphological disruption of cellular homeostasis within the muscle’s cytoskeleton and extracellular matrix (think: the muscle’s scaffolding).
>This study found that short-term resistance training programs create relatively large amounts of muscular damage but do not create much true hypertrophy.
>Contrastingly, it was found that long-term resistance training programs create much smaller amounts of muscular damage but create much greater amounts of hypertrophy.
>These two findings demonstrate an apparent disconnect (a negative/inverse relationship) between muscular damage and muscular hypertrophy.
>Seemingly, each pathway—the muscular repair and muscular hypertrophy pathways—compete over protein resources.
>Furthermore, muscle protein synthesis seems to allocate its resources sequentially only producing muscular hypertrophy after the required repairs are completed.
>These researchers concluded that muscle damage does not directly create muscle hypertrophy. Moreover, they demonstrated that they, in some ways, act antagonistically.
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Take-home:
>Muscular damage, and therefore soreness, is not a requirement for cross-sectional hypertrophy (radial muscular growth).
>Excessive muscular damage/soreness appears to diminish muscular hypertrophy due to the muscle protein synthesis response being biased towards tissue repair rather than subsequent growth (the typical goal).
>It should be noted that there are many strength/resistance training variables that certainly do lead to muscle growth while simultaneously increasing the likelihood of causing some damage/soreness (e.g., increases in muscle tension/load, increases in volume, etc.). Some occasional light-moderate soreness should still be expected from a high-quality strength program.
>As a final note, while muscular damage may not be directly connected with cross-sectional hypertrophy, it may be mechanistically connected with longitudinal hypertrophy (growth increasing muscle length). That is an entirely different topic.
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Sport-Specific Agility Training
Advanced athletes don’t utilize bunk agility training methods.
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Young & Farrow (2013). The Importance of a Sport-Specific Stimulus for Training Agility. Strength and Conditioning Journal, 35(2), 39-43.
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The purpose of this study was to review the available scientific literature to provide guidance to coaches and athletes towards more effective agility training methods. Practical applications were reviewed and a close look into what constitutes effective training stimuli for the development of sport-specific agility.
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In this study/review:
>Agility is a highly complex physical attribute. It is best described as being the product of perception and decision-making skills combined with change of direction (COD) speed, which additionally has strong components based in strength and power. Consider this over-simplified equation as a description:
Reactive Decision-Making (X) Speed (=) Agility
(a more comprehensive version can be found here)
>Perception and decision-making skills entail scanning for sport-specific stimuli (e.g., opponent’s movement/actions) and deciding what physical response would be the most efficient and effective tactical response.
>After the decision-making process is completed, the applicable COD skill must be quickly executed to complete an action that is considered a demonstration of agility. COD skills are things like acceleration, deceleration, cutting, turning, backpedaling, side-stepping, and other similar agility-related movements.
>There are both non-specific and sport-specific methods of practicing/training agility:
1. Non-Specific Agility Methods
>Non-specific methods are either pre-planned COD drills (e.g., “5-10-5” and “T”-drills) or reactive drills that are generic (flashing lights or sound-based drills).
>These aim to improve COD rather than agility, per se. Numerous research studies have shown that these methods do not directly transfer to sport-specific agility or sport performance.
>Non-specific methods can be useful in the short-term for young, elementary, and beginner athletes that need to improve basic motor skills but should not be utilized for long-term development as they do not improve the greater aspects/requirements of agility.
2. Sport-Specific Agility Methods
>Sport-specific methods include all aspects of agility that transfers to the respective sport—perception, decision-making, and COD.
>These methods are best utilized in sports practices rather than in the gym. Examples of these methods include scrimmages, small-sided games, and evasive drills that emphasize the tactical scenarios of a greater game. Ultimately, practicing the sport in various ways is the best way to develop the reactive components of agility.
>Sport-specific methods are long-term solutions to develop agility in intermediate and advanced athletes trying to improve their direct sport performance.
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Take-home:
>Pre-planned and/or generically reactive (flashing lights) drills do not directly improve sport-specific agility.
>Although these methods have a window of usefulness within the context of lowly skilled, beginner athletes needing to practice basic COD skills, real agility development requires actually practicing the sport aimed to be improved. This is because real agility requires reaction to sport-specific rather than generic stimuli. This is best achieved under the guidance of a knowledgeable sports coach.
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In-Season Strength Training is Required.
It’s all too common for athletes to take their off-season and pre-season strength training seriously, but then completely neglect their in-season maintenance program. In-season performance will be lost and the risk for injury will sharply increase.
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Kraemer & Nitka (2023). Importance of an In-Season Strength Training Program: A Reminder to Sport Coaches. Strength and Conditioning Journal, 45(3), 379-383.
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The purpose of this study was to review the multi-faceted importance of in-season strength training and to (re)educate sports coaches [and parents] to better make these values known. The in-season portion of the training calendar should not be omitted.
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In this study/review:
>Unfortunately, the value of in-season strength training has been lost amongst sports coaches [also: athletes and parents].
>There are, at least, 3 major tenets that make in-season strength training programs highly important/necessary for athletic development, health, and sport performance:
1. Increased Sport Performance. The maintenance/improvement of strength levels during the season assures increased performance as the sporting season prolongs. Without strength training, detraining occurs, and performance outcomes are lost. This has additional implications that affect injury risk and multi-sport preparation.
2. Increased Injury Prevention. Detraining is a known risk factor for injury. Preventing detraining will inherently decrease the risk for sport-related injury. Keeping muscle and tendon tissues thick, dense, and strong constitutes frontline protection against soft tissue injuries. Furthermore, in-season strength training has been shown to maintain high levels of repair-remodeling mechanisms which assists in-season athletes in recovery between practices and competitions/games which improves resiliency.
3. Increased Multi-Sport Preparation. For multi-sport athletes who are expected to transition from one sport to the next, the first sport’s in-season training constitutes pre-season/off-season training for the upcoming sport. If in-season detraining (loss of strength and performance) is allowed, then this athlete will be even more ill-prepared for the following sporting season. This creates a further cascading effect for diminished sport performance and increased risks for future injury.
>Strength coaches should consider these in-season program variables for effectiveness and periodized appropriateness:
1. Training Frequency & Timing. Twice per week strength training has been shown to at least maintain, if not improve, strength and performance variables during in-season sports. Training sessions should be appropriately spaced between each other and competition to assure recovery. Furthermore, training sessions should not be immediately before or after sports practice to avoid ineffective training due to accrued fatigue. Lastly, training sessions should not be early morning as this limits effectiveness and produces endocrine-related stress.
2. Exercise Variables. Exercise selection should focus on whole-body, compound movements and sport-specific injury prevention exercises. Exercise intensity should remain high to maintain or improve strength variables. Loading should emphasize both high-force/low-velocity and lower-force/higher-velocity movements. Volume (number of hard sets) should be attenuated to enable recovery resources to be allocated towards practice and competition. Rest intervals should be high (around 3 minutes) for heavy resistance exercises and shorter (around 2 minutes) for rehabilitation, injury prevention, and other supplemental exercises.
Conclusion:
>In-season strength training is necessary to maintain or improve the physical abilities required for sport performance. Additionally, the maintenance of these physical abilities act to defend against the risk of injury. Lastly, sport coaches [and parents] need to be educated to these facts to prevent athletes from ceasing their training responsibilities.
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Take-home:
>A high-quality, periodized in-season strength training program is non-negotiable for any serious athlete concerned with sport performance and injury prevention.
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Myth: Proprioception Training
As popular as proprioception (and balance) “training” is amongst physical therapists, sport coaches, personal trainers, and strength coaches, it remains misconceived, ineffective, and unsupported.
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Kim et al. (2011). Overcoming the Myth of Proprioceptive Training. Clinical Kinesiology, 65(1), 18-28.
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The purpose of this study was to review the available scientific research on proprioceptive/proprioception training (as a factor within improved balance), to define it more precisely, and to evaluate its effectiveness.
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In this study:
>Proprioception is defined as sensory input information which describes joint, limb, and overall postural position, velocity, and direction.
>There are two primary misconceptions that cloud proprioception training. One is that exercise/training can improve it. The other is that proprioception is automatically an underlying factor for improvements in balance tasks.
>The origins or proprioception training (exercises aimed at improving this sensory information) are rooted in clinicians (i.e., physical therapists) that have assumed that balance tasks with unstable surfaces would challenge proprioceptors and subsequently improve their function. This presupposition is unfounded.
>A multitude of previously conducted studies have created increased confusion because any measurable improvement within balance tasks have been incorrectly reported as improved proprioception without actually measuring any neurophysiology of the proprioceptors.
>The proprioceptors (muscle spindles, golgi-tendon organs, and joint capsule/ligament receptors) have not been demonstrated to improve signal velocity or general acuity (the factors that would constitute meaningful change in function) with these types of physical interventions.
>Between aforementioned false presuppositions and poorly defined scientific outcomes, the myth of proprioceptive training continues to persist.
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Conclusion:
>There has been little scientific research conducted that directly measures proprioceptive function. Amongst the little research that has been done, there is no support of proprioception’s trainability via physical training/exercise.
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Take-home:
>Emphasizing proprioception and allowing its influence over exercise programming is discouraged due to the lack of evidence supporting its effectiveness.
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Shortcomings of Stretching
Chronic, traditional stretching practices often fall short of the desirable physical outcome. There are much better ways of improving flexibility, mobility, or range of motion.
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Freitas et al. (2018). Can chronic stretching change the muscle-tendon mechanical properties? A review. Scandinavian Journal of Medicine & Science in Sports, 28(3), 794-806.
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26 studies were selected, reviewed, and analyzed based on the inclusion criteria:
1) Longitudinal interventions using human participants.
2) Static, dynamic/ballistic, and/or PNF stretching interventions/protocols.
3) At least 2-week long interventions (most were 4-8) with at least twice/weekly session frequencies.
4) Measured at least one joint or muscle-tendon structural/mechanical variable.
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In this study:
>Chronic stretching (up to 8 weeks) did not seem to improve muscular or tendinous qualities.
>Chronic stretching mainly altered the sensory system (increased stretch tolerance).
>Chronic stretching did not improve muscular length (e.g., serial sarcomeres, fascicle length).
These findings suggest:
>Traditional stretching only improves the sensory effects on the nervous system.
>Traditional stretching fails to improve any mechanical adaptations of the muscle-tendon unit.
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Take-home:
Traditional stretching strategies often fail to produce desirable muscular adaptations. There are better ways of improving flexibility, mobility, or range of motion.
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Strength Training for Sprinting Speed & Performance
Muscular size and strength matters for sprinting speed and performance.
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Miller et al. (2021). The Muscle Morphology of Elite Sprint Running. Medicine & Science in Sports & Exercise, 53 (4), 804-815.
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3 groups compared:
5 elite sprinters (100m <10.25 s) w/ competitive sprint training and resistance training.
26 sub-elite sprinters (100m 10.35-11.50 s) w/ competitive sprint training and resistance training.
11 control participants (no more than moderate, unstructured weekly physical activity).
Body composition, muscular size, and muscular strength were compared between groups and compared with sprinting performance.
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>All sprinters were substantially stronger than the physically active but untrained control group. They were most notably stronger in the muscles that control the hips and knees.
>Elite sprinters had the greatest muscle mass amongst all three groups.
>Perhaps counterintuitively, elite sprinters are significantly heavier than sub-elite sprinters due to their added muscle mass.
>Elite sprinters have substantially greater muscle volumes in 4 compartments of the legs. This greater muscularity specifically pertains to hip extensors, hip flexors, knee extensors, and knee flexors.
>Hip extensor size (e.g., glutes) was responsible for 47.5% of the increased performance.
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Take-home:
If you’re an athlete that wants to be fast, sprint-specific strength training is a must.
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