The Effects of Resistance Training to Near Failure on Strength and Hypertrophy
Written by Ben Bunting: BA, PGCert. (Sport & Exercise Nutrition) // British Army Physical Training Instructor // S&C Coach.
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Strength training using different loads, rep ranges and movements is proven to maximize muscle growth while increasing training volume and burning more calories than ever.
Studies suggest that resistance training near failure is not optimal for maximizing muscle gains, particularly when its definition changes over time.
Training to Failure
Training to failure challenges your nervous system to recruit larger fast-twitch muscle fibers from within to overcome resistance, leading to strength and hypertrophy gains in muscles.
Unfortunately, training to failure requires fatigued muscle fibers undergo an anabolic recovery process in which they must resynthesize energy depleted during each set in order for full anabolic gains to take effect - thus leading to sore muscles after each training session in which you train to failure.
This may explain why you feel discomfort after each session in which training to failure takes place!
The goal of one study was to examine whether resistance training (RT) performed until momentary muscular failure (a catchall term for set termination criteria for various definitions of failure in studies) is more beneficial when total volume load is equalized than non-failure RT, and whether proximity-to-failure threshold velocity loss affects muscle hypertrophy.
As such, a systematic literature review and meta-analysis were conducted of studies which explored the effects of resistance training to failure or not on muscle hypertrophy by searching the PubMed, SCOPUS, and SPORTDiscus databases.
19 studies compared RT performed to momentary muscular failure with that not performed to momentary muscular failure, and this meta-analysis demonstrated that performing it to momentary muscular failure did not result in greater muscle hypertrophy than performing it otherwise when their total volume were equalized; however, due to velocity loss thresholds being different and therefore indirectly influencing outcomes of hypertrophy outcomes.
Furthermore, studies included in this meta-analysis varied significantly in terms of training level, body region and type of exercises performed.
Due to such diversity it is hard to draw firm conclusions regarding the efficacy of resistance training performed to momentary muscular failure compared with other methods for increasing muscle size and strength.
Shorter Rest Periods
Weight training has historically been used by elite athletes who compete in sports such as powerlifting, Olympic lifting, bodybuilding and football. Such athletes require high levels of strength and muscularity which can be attained using heavy weights with long rest periods between sets.
Recently, studies have demonstrated that circuit (short rest) resistance training can increase both the content and oxidative capacity of muscle mitochondria - changes which are thought to improve a muscle's resistance to mechanical stress. Furthermore, standard resistance training was found to reverse mitochondrial degeneration associated with age in skeletal muscle.
Resistance training to near failure offers many advantages for muscle fibers of type II muscle types. Mechanical tension must be high enough so they can produce maximum force production during sets.
However, high levels of acute neuromuscular fatigue could suppress force production via central and/or peripheral mechanisms in muscles; possibly explaining why resistance training performed to both momentary muscle failure and non-failure produces similar standardised effect sizes for changes in muscle size pre/post intervention.
Other factors can impact the effectiveness of RT to near-failure. These include how the set failure definition is understood, whether a single set or multiple sets are completed and velocity loss during sets.
Meta-analytic results showed that RT to near-failure was no more effective than RT performed under moderate (ES = 0.39) or high velocity loss conditions (ES = 0.42).
Studies have also highlighted the significance of frequency when it comes to resistance training sessions. When training a muscle daily, increases in strength and hypertrophy are more dramatic than when done only twice weekly.
As resistance training to near-failure results in considerable muscle damage and systemic fatigue, it is crucial that adequate rest between workouts be provided for recovery and repair to occur as well as increase training intensity levels.
Furthermore, taking adequate rest between sessions increases total volume worked completed - essential factors when trying to build muscle mass.
Can training to failure lead to catabolism?
Resistance training (RT) programs involve many variables that can have an effect on its results, including frequency, volume, load, tempo and exercise selection or order.
All of these elements could impact hypertrophy growth of muscle mass in your body - making it vitally important to take all variables into consideration when designing your resistance training (RT) plan.
Studies comparing resistance training performed until momentary muscular failure with non-failure RT have generally found no significant differences.
However, these results should be taken with caution as current methods used to control set termination during non-failure RT may limit insight into its proximity-to-failure achieved and could inhibit any observed effects on muscle hypertrophy.
Train to muscle failure, and you will likely experience significant neuromuscular fatigue within one set.
This may result in reduced ability to do additional reps on subsequent sets - for instance if you do 10 reps to failure during one set, subsequent sets might only allow for 6 or 7 reps before becoming much harder due to central fatigue - the result of overtaxing your nervous system with training to muscular failure that cannot recover quickly enough.
Resistance training to near failure has also been demonstrated to cause extensive muscle damage, prolonging recovery from your workout session. This may lead to reduced anabolic hormone production which reduces muscle growth.
Resistance training to near failure may cause excess metabolic stress and fatigue, interfering with energy expenditure and recovery times. This is especially problematic for competitive athletes who often require higher volumes of training - including more sets and reps - in order to meet strength and performance goals.
Though resistance training to muscular failure initially produces beneficial gains in strength, its long-term consequences are uncertain.
The initial increase in strength may have arisen through neural adaptation - when nerves servicing muscles change their firing behaviour to fire more frequently (prompting increased muscle contraction) and recruit additional motor units (the individual nerve cells and associated muscle fibers involved with movement). Over time these firing patterns lead to an increase in strength without necessarily leading to larger muscles sizes.
Conclusions
Resistance training to near failure is a popular exercise technique that has been linked with increased muscle size and strength gains. Research also suggests it may reduce body fat while simultaneously increasing aerobic capacity in healthy individuals.
However, there has yet to be conclusive proof of these benefits in everyone - some research even indicates this type of training could even be counterproductive when building muscles or increasing strength levels in certain individuals.
Numerous studies have investigated the effects of resistance training to near failure on strength and hypertrophy, yet their findings vary dramatically. Some results could also be affected by various definitions of set failure or other variables; making comparisons across studies difficult.
A meta-analysis sought to improve their reliability by grouping studies according to their definitions of set failure or other potential factors that might alter results.
Those recorded results indicate a modest advantage to resistance training to momentary muscle failure over non-failure training for muscle hypertrophy, although other variables such as volume load and relative load could potentially alter this conclusion.
One explanation for the lack of effect that resistance training to near failure appears to have on muscle hypertrophy may be related to acute neuromuscular fatigue that increases as you approach near failure threshold, suppressing neural drive and excitation-contraction coupling and decreasing force output from muscles.
Another potential explanation may include release of high levels of lactate and growth hormone that interfere with protein synthesis.
No matter the purpose, it is essential to keep in mind that resistance training near-failure intensity is extremely taxing on the body and requires plenty of rest between sets to allow recovery.
Therefore, individuals should only train to muscle failure on the final set of each resistance training session when working towards specific goals (like increasing muscle size or increasing strength) with this type of hypertrophy training being done sparingly on days that specifically dedicate hypertrophy training sessions.
