Choosing the right weight to lift
The benefits of strength training are well known, and may include weight loss, improved strength, increased bone density and elevated energy levels. However, there is debate amongst the fitness community about the right amount of weight to lift.
Heavier weights are often recommended as the best way to improve muscle size and strength with the amount of weight to lift usually expressed as a percentage of the most weight a person can lift in a single effort, or one repetition maximum (1RM). For example, if the most weight you can lift for a one-off bench press is 10 kilograms, then you might be instructed to perform 10 repetitions at 80% of your 1RM (10 lifts of 8 kilograms). Lifting a weight at 80% of your 1RM would be considered a heavy lift. Yet there are also advantages to be had from training with lighter weights (e.g. 30% of 1RM), including:
- Improved safety
- Improved control over movement and technique at the end of a set (as the difficulty increases)
- You don't need a spotter when training with lighter weights
- Light weights are ideal for beginners to strength training, or those recovering from injury
To help settle the debate as to the best method of training, a study published in the Journal of Applied Physiology
compared heavy and light weight lifting programs over 10 weeks. The subjects trained three times a week, and were divided into the following three groups:
- A heavy lifting group performing one set at 80% of maximum
- A heavy lifting group performing three sets at 80% of maximum
- A light lifting group performing three sets at 30% of maximum
All groups were instructed to lift to failure in each set, where momentary muscular fatigue meant they could no longer perform any further repetitions. The heavy lifting groups typically performed 9 - 12 repetitions per set, while the light lifting group performed up to 30 repetitions per set.
The researchers discovered that the heavy and light groups who performed three sets achieved equal improvement in muscular growth and strength. The group who performed one set at 80% of maximum still saw an improvement, but this was 50% less than both the three set groups.
Practical implications for your strength training routine
Knowing that equal benefits can be obtained from lighter weights could be encouraging for many. For example, some women and older people (who both stand to gain significant benefits from strength training due to their lower levels of muscle mass), may feel intimidated by heavy weights. The following guidelines show you how to obtain equal benefit from lighter weights.
- Lift to fatigue - For light weights to be equally effective as heavier weights, muscle fatigue needs to be achieved. This involves lifting a weight to the point where you can no longer perform any further repetitions. If you need to lift a weight more than 30 times to achieve fatigue, it may be time to increase the weight slightly.
- Perform three sets - Subjects who performed three sets achieved double the muscle gain compared to subjects in the single set group.
- Train 3 times a week - Subjects in this study performed strength training three times a week, and achieved significant improvements in muscle volume and strength.
- Consider protein supplements to boost your results - Study subjects ingested a high quality protein supplement immediately after each weights session that contained 30 grams of protein to maximise the training response.
- Don't dismiss heavier weights - It will take more time and repetitions to reach momentary muscular failure with light weights compared to heavy weights. If you are limited for time or if you have been using light weights for several weeks and like the thought of some variety, heavy weights can still be beneficial.
References available on request