Partial Reps (Half Reps) vs Full Range Of Motion- What Works Best
One of the oldest tenets of weight training is the overriding importance of full range of motion (ROM) exercise for optimal muscular and strength development. Counter to this conventional approach, many bodybuilders, power lifters and athletes of numerous disciplines have successfully included partial range of motion repetition training protocols for decades with exceptional results, but mention anything other than executing an exercise through a complete range and tempers immediately flare. The idea of full range of motion training is ingrained in the formative training protocols of most fitness professionals and few are able to think outside of that sometimes narrow and restrictive box. Unfortunately, the hubris of an emotional response to a new and poorly understood training technique can often lead us away from a real and informed determination as to whether a particular training regime has any intrinsic value. The use of brief, low volume high intensity training as a viable, (and some might say superior), method of increasing muscle mass, endurance and reducing body fat[1,2,3,4] is a prime example. In this article we will take a hard look at one of the training methods that in many ways goes against the grain and explore whether there is any real merit to the use of partial repetition training for increasing strength and muscle mass. Full range of motion versus half reps as partial repetitions are commonly called is a controversial subject, to say the very least, but after reviewing the research you may have a different point of view as to its practicality and potential usefulness in your own training program. Thanks as always for reading my work and do feel free to forward this article to someone you think would benefit from reading it.
Partial Range Of Motion Repetitions (Half Reps)- What Are They?
A partial repetition (or rep- which is the wording that I will use mostly throughout the article) is defined as a movement that is executed within a restricted portion of a lift.  In the cases of partial rep training, the range of motion focuses on the upper range or completion phase of the repetition. For example- in a squat a partial rep would be a half or quarter squat where you do not descend to the parallel plane or below, while in a bench press a partial rep would consist of a limited range of motion in the final 2-5 inches of the lift right before full extension of the elbows.[5.] Muscular strength varies throughout the full range of motion of any given joint due to muscle length-tension relationships, muscular activation and overall muscle mass.[6,7,8,9,10,11] If you were to plot on a graph the variations in strength during any weight bearing exercise you would see that the upper range corresponds to the area of the highest force output. Partial reps are an advanced mode of training used by numerous athletes in various sports where the idea is to train in the range of motion where there is maximal force production. One application of this form of training is to overload the musculoskeletal system with extremely heavy loads in the area of range of motion where maximal force is produced. Given the smaller range which describes the range of motion where your muscular force is greatest, it is possible to lift supramaximal loads- which are weights greater than 100% of your one repetition maximum (1-RM)  Several studies assert that this form of training is in some ways superior to full range of motion training for increasing muscle mass and overall as it allows for the use of much heavier weights. [13, 14]
The Argument For The Use Of Partial Reps
Partial reps confer a substantial mechanical advantage as you are able to handle considerably heavier weights. Training with heavier weights through your strongest range of motion means that there will be a far greater degree of overload experienced by the muscles being exercised. Overload is an important variable in terms of increasing muscle strength and size. Without significant overload, there is no reason for our bodies to trigger the adaptation response that makes our muscles bigger and stronger. (Read my article on How Muscles Get Bigger & Stronger for more information on the importance of overload and the adaptation response.) That being said, the ability over time to move heavier weight will trigger the adaptation response and muscles will get larger and stronger as a result. Ligaments and tendons will also become stronger, further increasing the potential for increased strength. Another important argument for the use of partial reps is its relevance in what is known as the carryover effect. Execution of full range of motion on almost all conventional weight lifting exercises does not resemble everyday activities or those relevant to athletic and sporting activities. Consider the punch of the boxer or the swing of a baseball bat- all movements that are far closer to a partial movement than a full a range of motion exercise that you would ordinarily see in the gym. In everyday activities we usually act with our arms almost fully extended and since partial reps are more specific to these real world activities there should be more of a carryover effect in terms of enhancing performance of these movements.
Partial Reps Are Closer To Real Life Movements Than Full Range Of Motion Reps
A prevailing theory of sports specificity is that the closer a training protocol resembles an athletic ability, the higher the likelihood that gains from the training will translate into greater athletic performance. [15,24] Consider for example the execution of a half squat versus that of a full squat. Many an old school gym goer might turn their noses up at someone not squatting to parallel or lower- but there is some merit to training in this manner- both for those seeking improved athletic performance and increased strength in a full squat. In a full squat the amount of weight you use will always be limited to how much you can handle through what is referred to as ‘the sticking point’. In a squat this occurs somewhere around the mid to lower range of the exercise (between the joint angles of 95 and 115 degrees approximately), and when performing the exercise it becomes relatively easier once you have ascended past this point. This is because the weight required to bring about overload in the lower range of a squat is not enough to overload the leg muscles in the upper range between the joint angles of 140-180 degrees. In fact, on average most people can lift anywhere in the ballpark of 150% more weight in the upper range of a squat and the argument is that not working with adequate overload in this range you are missing out on realizing your full strength potential.
Partial Reps Confer Athletic Benefits Not Possible With Full Range Of Motion Reps
It’s an argument that is not without some apparent logic as execution of almost all athletic type movements- from jumping to get a basketball, to riding a bicycle occur within a small range of motion as we mentioned previously. Thus it makes sense to train with heavier weights in this range to maximize your athletic performance. A heavy half squat, as maligned as it may be by many gym purists, confers force production and athletic performance benefits that full squats simply cannot replicate and is one of the reasons athletes use partial rep training with supramaximal loads to improve their performance. This form of training was extremely popular in the former Soviet Bloc with many athletes in the West adopting these principles after seeing how effective they were in helping athletes from behind the Iron Curtain excel in the Olympic Games. 
Can Partial Reps Increase Overall Strength
While we can say with some certainty that partial reps can allow for heavier weights in small ranges of motion, the question remains whether this confers increases in strength throughout the full range of joint movement. Interestingly enough, physical therapy studies and interventions show that they do indeed carry over. The majority of studies using partial range of motion training were performed on clinical populations in which the patients had limited range of motion to begin with. These studies show without question that partial range of motion training increased isometric strength within the specifically trained range of motion of the exercise and throughout the full range as well. [16,17] Other studies using isometric training have demonstrated that movements executed within a specific joint angle can result in a ‘spillover’ of strength of plus or minus twenty degrees from the trained joint angle.[9,18,19] Neural adaptation could play a part in such spillover as the muscles learn to recruit and fire more motor units in response to a new load bearing exercise, especially during the first several weeks. . This could account for some strength transfer although other studies have shown increased strength throughout other ranges after partial repetition isometric training for a period of 16 months. 
These studies mostly focused on isometric training in a rehabilitative setting, but in a more gym specific environment several researchers have investigated the influence of partial range repetitions on overall range of motion strength. The findings show that such training protocols do indeed have a positive effect on increasing strength throughout the full range of joint movement on several tested exercises. [16,17,22, 23] One study looked at the differences in strength increases among regular strength trained male volunteers doing full range versus partial range of motion bench presses. Participants were tested their 1 repetition maximum (1-RM) bench press lift and their 5 repetition maximum lift on two separate occasions after training with full range of motion bench presses and then after training with partial range of motion bench presses. The results showed that partial range of motion performance increased significantly for both the 1-RM and the 5-RM while no such improvements were observed for the full range of motion movement.  Such results are notable, and researchers were quick to add that these individual who ordinarily trained using full range of motion movements may have experienced improvements due to an increased motor learning response and because they failed to regularly train in the area where maximal force development occurs. By increasing their biomechanical advantage during lifts by simply eliminating the ‘sticking point’ they are able to use much heavier weights than usual.
Partial Rep Training Is As Effective As Full Range Of Motion Training Under Some Conditions
A longer duration 10 week bench press study of recreational, drug free weight training men took a look at the results of partial repetition training in a controlled setting where subjects were not allowed to do any weight lifting activities outside of their assigned exercises in the study. Participants were put in three groups- one group doing partial range of motion repetitions only, one group doing full range of motion repetitions only and one group trained using a combination of partial repetitions and full range of motion reps. Training was done twice a week and included basic compound movements for the entire body such as squats, rows, curls, pull-downs, leg curls, calf raises and crunches with the emphasis on bench presses. For bench presses the partial repetition group trained at or above 100% of their 1-RM within the upper portion of the lift just above the sticking point near full extension of the elbows. The full range of motion group started out at 65% of their 1-RM- with all groups performing three sets of 15 repetitions.
At the end of the 10 week program subjects were tested on their one repetition maximum (1-RM) on the bench press through a full range and the findings were not at all what one might expect. Participants in ALL groups experienced significant increases in strength, with those in the full range of motion group experiencing almost identical average increases in their bench press maximum of between 25 and 24.33 pounds. Strength increases in the combination range of motion group however was a bit lower at 16.5 pounds on average. Given the idea that overload is the most important determinant in whether or not muscular adaptation is triggered to increase strength and size- advocates of partial rep training might expect that those doing only partial reps would have the greatest gains in strength, but this was not the case. On the other hand, since those doing partial reps never did a full rep, advocates of full range of motion training might expect them to not be as strong as those doing exercises through the full range- but this was not the case either as gains were about equal either way. Thus partial repetitions were found to be equally as effective as full range of motion training within the parameters of this study. 
Partial Rep Training- Aerobic & Fat Burning Benefits
Researchers have found that greater force generated in the upper range of an exercise can make the overall training session more intense and help you get more out of your workouts. Studies of partial repetition barbell curls in the upper range showed that it not only allowed for the production of more force (torque) but also accentuated the cardiovascular response to the exercise as compared to full range of motion curls.Heart rates were higher as was blood lactate, PH levels and perceived degree of exertion among subjects in the study. Researchers theorized that the restricted range of motion allowed for an increase in the speed and rate of motion in the performance of the partial repetition- thus increasing the amount of work performed in a set period of time. The more work you do the greater the training effect and this aspect of partial rep training is one that many schooled in high intensity techniques will immediately recognize. As it goes a long way in bringing about a greater overall conditioning effect. The increased intensity also leads to greater post exercise oxygen consumption (EPOC) as the body has to burn more calories to return to homeostasis. An afterburn effect that has been shown to be an effective method for fat loss, thus those interested in shedding extra pounds may want to integrate some partial rep training into their programs. Such intensity also have an increased cardiovascular benefit and should be of interest to those keen on increasing aerobic fitness as well. Training at high intensities isn’t the only way to increase strength, but i might be one of the most efficient ways to get stronger and tone up in the process.
Partial Reps- When Are They Best Used
Partial repetition training is without question a useful tool in the arsenal of anyone serious about peak performance, increasing strength, lean muscle mass, aerobic capacity and decreasing body fat. Advanced athletes at a sticking point would benefit greatly from a program incorporating partial repetition training, especially when they reach a plateau where little or no progress occurs. Data shows that integrating partial rep training with full range of motion leads to notable increases in strength. Increases that over time should amount to gains in lean muscle mass as well. Many of the studies were considered too short (only 8-10 weeks) to see any measurable increases in muscle mass- but a long term inclusion of this protocol should present some gains in this area.[2,3,9]) On a personal note, I have included partial repetition training as a powerful tool in our Naturally Intense High Intensity Training™, and I can say after 22 years of doing it and teaching it that it does indeed go a long way in increasing intensity, muscle strength and size, especially among advanced athletes. One use that was invaluable to me as a teenager was in the idea of dis-inhibition.We all have built in fail safes that stop us from lifting heavier weights. Far more than simply an unreasonable fear, it is a function of our central nervous system to signal our muscles to shut down when a load placed on our body is too high. It’s a useful mechanism that helps us from injuring ourselves on a regular basis by trying to lift trucks and such, but it can also stop us from training with the weights we should be using if maximum strength is your goal. As a teen, 315 lbs was about the heaviest weight on the planet for me. I couldn’t conceive of anything being heavier for a full squat. So over time my coaches had me do half squat movements with as much as 450 lbs- with the idea of getting me accustomed to the heavier load. Sure enough, it did work and I was able to squat over 405 lbs in a full squat over time. This concept of dis-inhibition is one that is well documented and often used by strength athletes since using heavier weights in smaller ranges of motion does reduce the overly sensitive nature of of our protective mechanisms, thus allowing the individual to get closer to their absolute maximum lifting abilities.
Partial reps can also be used as a tool to increase training intensity by using them at the end of a full range of motion set after reaching or approaching momentary muscular failure. If you are doing barbell curls for example and can only do 10 reps with a given weight- you could do 10 reps and then get another few reps by working in the upper range of the movement as you are mechanically stronger in that range. That way you can significantly overload your muscles and the increase in intensity will help you retain the benefits of the training session longer and help you burn more calories in the process. Using partial reps in this manner also reduces the amount of weight you would ordinarily lift doing straight partial reps as you won’t be in the supramaximal range but will still create a high degree of muscular overload. That way you stay safer by not lifting as heavy a weight but still get the benefit of partial reps training- a technique we regularly employ with Naturally Intense High Intensity Training.
As great as they may be partial reps should not replace full range of motion training completely, as full range of motion movements also have considerable benefits. Increased flexibility naturally occurs over time when training with resistance through a joint’s full range of motion- (think of it as yoga with weights if you may) and training with supramaximal weights consistently means that there will be a greater risk of injury over time. Since muscles don’t have much in the way of opinions but respond best to stimuli that they are unaccustomed to- it makes sense to judiciously add some partial rep training to your program and keep varying it with many other training principles as well. Partial repetition training is another tool like many others that you can use to keep your muscles challenged and constantly needing to get bigger and stronger to adapt to your ever changing routine.
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