High Reps & Low Weight Vs. Low Reps & Heavy Weight.

The question of low weight high reps or heavy weight low reps has raged on for years in the bodybuilding world. Most texts point towards a middle range being superior for muscle hypertrophy which is around 8 – 12 reps. However multiple elite bodybuilders all utilise slightly different training protocols to reach their level, some do high reps and high time under tension (TUT) with others sticking with some strength work and some do strength work with extra higher (bodybuilding) ranges being peppered within.

Muhdo gives clients a TUT range to use from the DNA results, this range changes to the goal they wish to have whether that be bodybuilding, endurance or power. Throughout data gathering certain correlations begin to show and these can be used to further DNA testing algorithms.

The gene ACTN3 has long been linked with power output with multiple texts linking those with the C variant with sprinting prowess [1].

One of the many genes tested by Muhdo is this gene, in particular the SNP rs1815739 and through some study we have found the following.

In male Caucasian bodybuilders (n=19) aged between 23-25 with a minimum of 2 years experience in resistance training showed a better hypertrophy response from some strength training being incorporated into their programme if they had the CC variant in ACTN3 (rs1815739).

The intervention is simple – to complete 4 main compound movements with a 5×5 (3s per rep) protocol (instead of the standard 6-15 reps) which was used over 8 weeks with a progression of resistance every 2 weeks if applicable/possible.

The exercises in question:

Flat Bench BB

Deadlift Standard BB

Back Squat BB

Cable or Bent over Row (BB)

How did the results look?

Average Results Table:

  Arm Circumfrence (flex) Inch Pre Arm Circumfrence (flex) Inch Post Upper Leg Circumfence Inch Pre Upper Leg Circumfrence Inch Post
CC 16.5 17.42857143 27 28.28571429
TT 16.28571429 15.71428571 26.5 26.35714286
CT 16.1 16.2 25.9 26.4


The CC variant group showed the best results with nearly an inch extra on the arms and over an inch on the thigh. However the other two groups showed little difference, showing that it may be a particular few that gains this benefit.

participant ACTN3 (rs1815739) Arm Circumfrence (flex) Inch Pre Arm Circumfrence (flex) Inch Post Upper Leg Circumfence Inch Pre Upper Leg Circumfrence Inch Post
DOX1 CC 15.5 17 27 28
DOX2 CC 16 16.5 28 29
DOX3 CC 17 18 26 27
DOX4 CC 16.5 17 25.5 27
DOX5 CC 15.5 17 28 30
DOX6 CC 17 18 27 29
DOX7 CC 18 18.5 27.5 28
DOX8 TT 17.5 16.5 26 25.5
DOX9 TT 16 17 25.5 25
DOX10 TT 17 15.5 27.5 27.5
DOX11 TT 15 16 26 26
DOX12 TT 15.5 15 27 27
DOX13 TT 16 15 28 27.5
DOX14 TT 17 15 25.5 26
DOX15 CT 18 18 26.5 26
DOX16 CT 15 16 27 28
DOX17 CT 15.5 15 26.5 27
DOX18 CT 16 16 25 26
DOX19 CT 16 16 24.5 25


Overall more research into the area is required to come to a decision on why this affect was occurring in the CC group. Chris Collins from Muhdo explains:

“Looking at just one gene and one snp is useful in designing a robust algorithm to help create a persons training plan, however it must always be taken as one of many gene variants and environmental factors that decide upon a training outcome”