One of our most recent blogs "Why do I experience muscle soreness after training?" left us pondering the question… 'is DOMS responsible for muscle hypertrophy?'... here we have attempted to answer this question as simply as we could.
To begin, it is important to know that muscle hypertrophy is the increase in skeletal muscle as a result of the increase in its component cells (sarcomeres and myofibrils). It is thought to be evoked by a sequence of processes including muscle activation; muscle deformation; signalling pathways & inflammatory responses; & protein synthesis.
Pictured: Arnold Schwarzenegger (left) & Calum Von Moger (right)
Many people consider DOMS to be indicative of a successful training session, but does muscle damage really mean your putting on the mass & you'll be looking like your bodybuilding idols in no time?
Evidence for damage induced muscle growth is based on the fact that DOMS are predominantly caused by eccentric exercise. This is because eccentric exercise is considered to induce greater amounts of hypertrophy when compared to concentric and isometric exercises, as well as a greater magnitude of acute inflammatory responses.
Indeed the literature positions muscle damage as a contributing factor toward muscle hypertrophy, however it also reveals that hypertrophy can occur independently of muscle damage.
From personal experience, I'm sure many lifters would agree that they have experienced muscle development independently of DOMS.
Two other important mechanisms mediating the hypertrophic process include mechanical tension and metabolic stress.
When you lift weights through a full range of motion, the working muscles are placed under a combination of passive (stretch) and active (flex) tension. Dynamic movements incorporating both types of tension are important to achieving maximum muscle hypertrophy.
Metabolic stress results from an accumulation of metabolites, such as lactic acid. You can think of this as the 'burn' and 'pump' you experience during training.
Together, muscle damage, mechanical tension and metabolic stress are considered to be important processes in achieving muscle hypertrophy and should be considered when planning your next training session!
For example- you already know it is important to perform an entire range of motion to incorporate both passive and active tension, however given that muscle damage is predominantly caused by eccentric exercise, you should really emphasise the eccentric part of each lift. Metabolic stress can be facilitated by taking moderate resting periods thereby increasing metabolic build up. You want to be careful not to take too short a break, as your succeeding lifts may be hindered. Energy stores are usually replenished within 60 seconds so a rest period of 60-90 seconds would be considered adequate.
Although three mechanisms to muscle hypertrophy have been indicated, it is important to consider the many variables that will determine the rate and extent of muscle growth. Such factors mediating the hypertrophic response include an individuals genetic background, gender, age, initial amount of lean muscle, duration of training, technique, & volume.
References:
Neme Ide, B. (2012). Muscle Damage and Human Skeletal Muscle Hypertrophy. Biochemistry & Pharmacology: Open Access, [online] 01(05). Available at: http://dx.doi.org/10.4172/2167-0501.1000e124 [Accessed 9 Aug. 2014]
Schoenfeld, B. (2010). The Mechanisms of Muscle Hypertrophy and Their Application to Resistance Training. Journal of Strength and Conditioning Research, [online] 24(10), pp.2857-2872. Available at: http://dx.doi.org/10.1519/jsc.0b013e3181e840f3 [Accessed 9 Aug. 2014].
