Weight Training For Fat Loss?

Contrary to popular belief, advocates of heavy strength training claim that performing high reps with a low weight will not lead to a greater amount of calories to be burned and in fact this compromised ‘intensity’ could result in less fat being oxidised. Here we explore the concept of heavy weight training for fat loss and how it can benefit you.

Studies show when weight training with a high volume (e.g. 5 sets instead of 1 set per exercise) with short periods of rest in between (ideally 60-90 seconds) with a weight 75% of your 1 repetition max (or more), your body releases more growth hormone compared to when you perform higher reps with a lower weight. It is hypothesized that maximal effort is necessary for optimizing exercise induced secretion of growth hormone and that growth hormone release is related to the magnitude of exertion (Pyka 1992) and is attenuated with greater lactic acidosis (Gordon 1994).





Baltimore researchers wanted to see if strength training could increase the resting metabolic rate and norepinephrine levels in healthy 50- to 65-yr-old men. The subjects resting metabolic rate, body composition and the plasma concentrations of certain hormones known to affect resting metabolic rate were measured both before they embarked upon a 16-wk heavy-resistance strength-training program and after. As well as improving their 3 repetition maximum by 40%, results also showed an increase in Resting Metabolic Rate which they believed was due to the increased fat free mass (muscle) and increased sympathetic nervous system activity.

However there are exceptions to this rule and it may be recommended to perform high repetitions (e.g. 20-30) for abdominal and oblique training since it’s been theorized muscular endurance may be more beneficial for lower back health than for muscular strength. Furthermore, moderate repetitions with a greater resistance can increase muscular girth under the subcutaneous fat, particularly in men, who have greater potential for muscular hypertrophy. Increasing the thickness around the waist with existing abdominal fat may further increase bulk, particularly in men who typically have greater intra-abdominal and subcutaneous fat in this area. The abdominal musculature is composed of relatively small muscle mass as compared to the glutes, quadriceps, hamstrings, chest, and upper back. Performing high reps with a lighter resistance should not compromise metabolism or muscle increases, as would performing high reps with light resistance on other, larger muscle groups.


References:
Pratley R, Nicklas B, Rubin M, Miller J, Smith A, Smith M, Hurley B, Goldberg A (1994) ‘Strength training increases resting metabolic rate and norepinephrine levels in healthy 50- to 65-yr-old men.’ Journal of Applied Physiology. 1994 Jan;76(1):133-7.


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