Can You Build Muscle Using Half Reps? Rep Range Science
In the fitness world, it's common to hear advice that "full reps" are the way to go regarding resistance training to build muscles. Full reps means moving the weight or resistance throughout your joint's complete range of motion.
While many fitness coaches encourage full reps in most exercises, it is noticeable that elite athletes and physique competitors use a partial range of motion in their training. This sparked debate about whether it is good to incorporate half reps in workout routines or simply skip them out.
That said, can you build significant muscles using half reps? If so, which is better, full reps or half reps?
In this article, we'll take a deeper look at the science of range of motion in building muscles and improving other aspects of your fitness, and how to optimize your workouts.
Range of motion is simply defined as the degree of movement at the joint. This also refers to the distance a joint can move safely and naturally without injury.
For example, the knee can move from a fully straight (0 degrees flexion) to a fully bent (135 degrees flexion).
Completing the full knee flexion movement from fully straight to fully bent is called 'full reps.' On the contrary, 'partial reps' would be any rep performed without completing the full motion of the joint.
Your muscles are attached to certain parts of your bones and joints. As your muscles shorten and lengthen during each rep, your joints move along with your muscles, thus creating movements or motions.
Since muscles make the joints move, it is vital to understand how the degree of joint movements influences your muscles in terms of growth potential and strength.
Full reps require maximum contraction and elongation of your muscles during each rep. This puts more stress on the joints and muscles, resulting in increased muscle growth due to significant microtrauma in the muscles, which are required for building muscles.
Doing a partial range of motion means you voluntarily choose to cut the range of your movement to a specific degree.
Many claim that doing half reps allows you to lift more weight and train more. It also allows you to feel constant tension throughout the set since you limit the degree of movements in a specific range where you can get maximum tension.
Most scientific studies suggest that full reps are better for long-term growth by hitting more muscle fibers in the muscle groups.
While it is true that you can lift more and do more repetition using half reps, you also have to account for the total amount of work or tension you are putting in your muscles.
For example, doing more reps with heavier loads using half reps results in a total decrease in the distance the weight is moving, thus negatively affecting your total workload.
Cutting the total distance the weight travels also reduces your total work volume. Performing half-reps may trick you into thinking you are doing more work than you actually do.
However, it doesn't mean that half-reps have no place in fitness workouts and that you should completely ignore it.
Improves muscle growth
The mechanical tension in your muscles stimulates muscle growth and increases your performance over time.
When performing full reps, there are specific points where muscle contraction has ZERO tension at all. For example, the bicep curl exercise has little to no tension at the starting point and end range of the movement.
Studies show that half reps can significantly improve muscle size and performance by constantly putting the muscle under tension.
Half reps limit your movement to a certain degree, particularly at a mid-range where the maximum amount of stress in the muscle can be felt. This effectively eliminates the mini-rest periods you have when you do full reps.
An optimized half reps will make the muscles fully engaged throughout the set, thus creating a more challenging and physically demanding task for your muscles to overcome.
Performing cable exercises can also eliminate the mini-down time during weight training and ensure constant tension throughout the movement.
Although full rep training leads to more significant muscle growth, it is also worth noting that it leads to faster and greater muscle fatigue since you exert more energy and effort when lifting weights in full range.
For example, taller lifters commonly find themselves out of energy before they do enough repetitions of squats to really work their lower body. This is due to a longer bar path when performing full reps.
This means you may consider doing half reps instead if you are low on stamina. This will still induce enough metabolic gains to make considerable gains by amping your work intensity. This technique especially works well with drop sets.
Mobility issues can be a significant hindrance for many athletes and fitness enthusiasts. Half reps could be your friend if you have knee pain, tight hips, or stiff ankles that bother you during a certain lift angle.
Half reps can allow you to work around the angle you have an issue with. By modifying the movement to stay within a comfortable and pain-free range, you can still engage the target muscle group without causing pain or discomfort.
Here’s a plan you should try if you’re a woman:
And if you’re a man:
Half reps can help you correct weak points and muscle imbalances by allowing you to isolate and target weak areas or angles without putting undue stress on the joints.
For example, the bottom part of the squat is the common weakest position in squat exercises. Using half reps such as in-box squats or pin squats can limit your range of motion and help you focus more on building strength in weaker positions.
Half reps can make an exercise more effective for building muscles as more time is spent in positions where mechanical tension is the highest and when the metabolic stress is optimal for hypertrophy.
As you build the necessary strength and perfect your exercise form and technique, you can gradually progress to full reps and increase the weight you are lifting.
A burnout set is additional or extra reps you do at the end of a set to drive your muscles to near exhaustion. It is ideal to use lighter weights for your burnout sets.
Strategically using half-reps for your burnout set to fatigue your muscle could lead to maximum metabolic stress in your muscles and greater muscle growth.
A drop set protocol using half reps can also work well in fatiguing your muscles.
In theory, any exercise can be performed using half reps. However, there are several exercises where half-reps shine the most.
For example, a study shows that half reps on skull crushers result in 200% more muscle growth than full reps.
Here are some of the most common exercises that benefit from half reps:
- Bicep curls - Start the lift on 130 degrees of extension, going to full flexion
- Skull crushers - Don't lock out your elbows, and limit elbow extension to about 70%
- Lunges - isolate and better engage the quads by stopping at about 60-70% on the way down. Pausing for 1 second at the bottom 70% before moving back up can also make the exercise harder
- Hanging knee raise - increase core engagement and quad activation stopping at 80 degrees knee flexion before going to full extension again
Remember that science and personal experience form the core foundations of an effective exercise regimen. Leaning into both while understanding your body's unique needs is the secret to achieving your fitness goals.
Research and science quantify things in fitness for us to separate facts from gym traditions and misconceptions. Knowledge is continuously evolving, and they are guides that you can use to achieve your maximum potential in the gym.
Although full rep training outperforms half rep regimen in building stronger and bigger muscles, you can still use half rep exercises as adjuncts to your fitness routine and reap its unique benefits.