New Study Finds Higher Training Volume Increases Size Not Strength

Much like other debates in the current muscle-building discourse, the high reps with low weights vs. low reps with high weights argument seems to be settled by science, only for new evidence to emerge and reignite the discussion.

A new study, although not yet published, has shed light on the effects of training legs to maximal levels with or without additional sets of high reps and lower weight, closer to failure. The research suggests what we believed to be true: higher weights with lower reps are better for building strength.

The study, which was presented at the International Journal of Exercise Science: Conference Proceedings, aimed to determine the effects of two different lower-body training programmes.

One group focused solely on strength (S), while the other combined strength and hypertrophy (SH). The researchers investigated maximal strength, muscle size of the vastus lateralis (VL, the muscle on the side of the thigh), and patellar tendon thickness (PTT, the tendon that holds the patella in place) in untrained men over a six-week period.

27 healthy, untrained men were randomly assigned to either the strength focused group or the combined strength and hypertrophy group. Before and after the training period, the participants performed a one rep max (1RM) leg press test. Ultrasonography (ultrasound) was used to measure the VL at full extension and the PTT at knee flexion.

• The strength (S) group completed 16 training sessions that included maximal isometric knee extensions and three sets of one rep at 90% 1RM on a leg press.
• The strength and hypertrophy (SH) group performed the same training but added three sets at 45% of their 1RM for as many reps as possible, stopping when they had two reps left in the tank.
• Training loads were increased every two weeks for both groups.

• Maximal strength (1 rep max on leg press): Both groups showed a significant increase in maximal strength after six weeks. There was no significant difference in strength gains between the two groups. Average strength increased from 599.48 lbs before training to 798.74 lbs after training.

• Patellar tendon thickness: Both groups showed a significant increase in patellar tendon thickness after six weeks. There was no significant difference in tendon thickness increases between the two groups. Average tendon thickness increased from 0.42 cm before training to 0.45 cm after training.
• Size of the VL muscle: The group combining strength and hypertrophy training showed a significantly greater increase in muscle size compared to the strength only group. The combined training group had an average increase in muscle size of 4.62 cm². The strength only group had an average increase in muscle size of 1.19 cm².

Both the strength and the strength and hypertrophy training programmes led to similar increases in maximal strength. However, the SH group experienced greater increases in muscle size compared to the S group. Despite this, the increase in patellar tendon thickness was similar between the two groups. The findings suggest that PTT adaptations may be more influenced by consistent high intensity loads rather than hypertrophy focused training.

If our goals are:

• To gain muscular strength: We are best to use higher weights working to maximal strength levels with lower reps.
• To gain muscular size: We are best to use lower weights with higher rep ranges.

This isn't to say we can't gain muscle size by working with higher weights and lower reps, but for strength, it is advantageous to lift heavier. Higher volume work is most important for gaining mass.

This isn't the first study to confirm these findings. A paper published by the Journal of Strength and Conditioning Research, compared high reps with lower weight and lower reps with higher weight, with both groups working to failure. The study found that both group's muscle size results were similar. However, for strength gains, the subjects using higher weights and lower reps saw the most benefit.

Ideally, a well-rounded programme will include a mix of the two approaches – training to a good intensity on a consistent basis. However, for a lower impact approach on tendons and joints, a lower weight with higher reps may be the best route. It's important to do what's right for you and your body.

Kate Neudecker

Kate is a fitness writer for Men’s Health UK where she contributes regular workouts, training tips and nutrition guides. She has a post graduate diploma in Sports Performance Nutrition and before joining Men’s Health she was a nutritionist, fitness writer and personal trainer with over 5k hours coaching on the gym floor. Kate has a keen interest in volunteering for animal shelters and when she isn’t lifting weights in her garden, she can be found walking her rescue dog.