Well, guess what? You don't!
Not only are partial-range reps perfectly "legal," they can be far more effective than full-range reps for building serious strength as quickly as possible.
Partial range reps, which I will refer to as "partials" from now on, are basically reps done in a specific range of motion. A partial bench press, for example, may involve doing only the top six inches of the range of motion.
Partial reps have one major advantage over full range reps: you can target your resistance to the specific range of motion you are working in.
Think of the bench press again. You know how much easier the weight feels after you get past the sticking point. Obviously, that sticking point is limiting the amount of weight you are able to use on the exercise.
If you are only able to get 200 pounds past the sticking point, but your chest muscles are capable of handling 300 pounds once you're past it, you will be limiting your ultimate muscle mass and strength levels by only using 200 pounds.
This is where partial training comes in. By working only in the range of motion ABOVE the sticking point, you can use far more weight and, therefore, work your muscles at a far higher threshold.
By working at a higher weight, you will not only be getting your muscles used to handling those heavier weights, you will be building your connective tissue to help handle those loads.
From personal experience, I know how dramatic the effect training the connective tissue to handle heavier loads can be. For years, I was stuck a maximum of 300 pounds on the flat bench press. No matter how hard I worked, nothing seemed to help. Then I discovered partials.
By working partials consistently, I brought my max bench press up to 350 pounds in a matter of months. It made me realize that my connective tissue strength was holding me back, not my muscle strength, and nothing builds connective tissue better than extremely heavy weights.
To give you an idea of the kind of weight your body may be capable of moving with partials, while at a bodyweight of approximately 210 pounds, I've done top range partial bench presses with 750 pounds and top range partial squats with 1100 pounds. Partials with this extremely heavy weight builds up incredible connective tissue strength and helps you build strength extremely quickly.
Partials are useful not only in the ranges of motion where you can use the heaviest weights, but in the ranges of motion where you are at your weakest.
Using the barbell squat for an example, think of where the weakest point in the range of motion would be. The very bottom, right?
Now imagine setting up a barbell in the power rack at the very bottom position of the squat. You get under the bar, then, starting from a dead stop, you squat the weight up a few inches then lower it back down to the safety rails again.
All of the stress of the exercise is placed on your muscles in their least favorable leverage, which will build up your weakest point. This can dramatically increase your strength and power in that weak range, which can have a dramatic effect on how much weight you'll be able to use for full range reps.
Partial training concepts can be applied to almost any exercise you can imagine, however partials are certainly more appropriate for some exercises than others. This is especially true of exercises that already have a short range of motion or need a full range of motion to be effective.
Some exercises partials work very well for include: bench press (a barbell is much better than dumbells as you can use the power rack rails to easily adjust your range of motion), squats, deadlifts, barbell and dumbell curls, barbell shoulder press, dips, close grip bench, pushdowns, bent-over rows, and calf raises.
Key Points About Partial Training
There are several very important things to note about partial training:
You should keep some full range movements in your program. Don't do partial movements exclusively for too long. I would recommend alternating sessions of partial and full-range training.
Training with extremely heavy weights is extremely demanding on the body. You may find you need more time to recover from partial training sessions than regular training sessions.
Because this training strongly affects the connective tissue, it's a good idea to supplement with nutrients that support the joints. These include Vitamin C (helps support collagen formation), calcium, glucosamine and chondroitin, MSM, and gelatin. These nutrients will help your body to recover faster from this heavy training.
Heavy partial training should not be done long term. I normally limit partial training to 6 weeks at a time, returning to full-range training for awhile. Taking time off partials not only allows your body time to recover from the extremely heavy weights but gives you a chance to put your newfound connective tissue strength to work in full-range training.
Describing how to do partials for every exercise I mentioned previously is beyond the scope of this article, but here are some pointers that will help you use partials in your workouts.
The power rack is your best friend. By setting the heights of the safety rails appropriately, you can stop the barbell at nearly any point in the range of motion of almost any barbell exercise.
Before you do a heavy partial rep, be sure to prepare yourself. Tighten up your muscles and prepare mentally. Partials are very different than full reps because of the far greater weights you'll be able to use.
Set aside your preconceptions of how much weight you're capable of lifting. You really will be amazed by how much more you can lift when you only work in your strongest range of motion.
Don't forget about working in your weakest ranges of motion too. It may not be as glamorous but working the weak range is very important for building up maximum full- range strength.
Work your poundages up gradually but don't be afraid to push yourself. Just because you can lift a ton more immediately doesn't necessarily mean you should. For the first few sessions, only go about 10 to 20% over your full range one-rep max. You need to give your body a chance to adapt to this totally different type of stress.
Your progress should be steady after that. Increases of up to 50 pounds or more per session are not uncommon on some of the larger muscle exercises such as bench press or squats. Try to move your poundages up each session, even if it's only by 5, 10, or 20 pounds.
Have fun!! You'll relish the incredulous looks you get from other people when you get to the point where you can lie down under a bar loaded with 7 plates on either side. You may have to apologize to others for using all the weight plates though!
To sum it up, partials are an extremely valuable training technique. They can help you blast through strength plateaus by building up not only your muscles and connective tissue, but your confidence with very heavy weights as well.
Bonus Training Tip!
Secret Training Tip #622 - High-Rep Partial Training
Gain strength and muscle mass!
This training technique is one of the best kept secrets for sending strength and muscle mass through the roof quick! Learn why it works and exactly how to do it for best results.
The partial rep is one of the most effective training techniques for building strength quickly but how can you adapt partials for boosting muscle mass at the same time? The answer is simple: high rep partial training.
Partial training, in a nutshell, involves only moving the weight in a shortened range of motion. This can be anywhere in the range of motion of an exercise but for our purposes, we're going to use the strongest range of motion, e.g. the top few inches of the bench press.
The reason conventional low-rep partial training is so effective for strength building is that you are using extremely heavy weight for low reps. This builds up excellent connective tissue and muscle strength.
Unfortunately for muscle gaining purposes, this type of training also results in a very short time under tension. Time under tension refers to the length of time a muscle is placed under continuous tension during an exercise. In order to stimulate muscle growth, your muscles need to be under tension for approximately 30 to 60 seconds (this is a rough estimate - it works out to about 6 to 12 reps in a conventional, full-range set).
A typical partial rep may take only one or two seconds to complete. If you do 5 reps, your muscles have only been under tension for 5 or 10 seconds. This is not nearly enough time to stimulate muscle growth. Now imagine doing 30 reps instead. This puts you right in the middle of that optimal range. Not only will you be using extremely heavy weight (which is great for building muscle and strength), but you'll be placing your muscles under tension for a long enough time to stimulate muscle growth. This is an extremely effective combination!
High rep partials can be used on their own or in combination with low-rep partials or even conventional full-range sets. I often use them after doing a few sets of extremely heavy low-rep partials. For example, I will do top range bench press partials with 600 or 700 pounds for low reps then remove a few plates and do a set of 50 or 60 reps with 315 pounds on the bar. I have also done sets of extremely high rep partial squats with extremely heavy weights (150 reps of 950 pounds). I've found both of these techniques to be very effective for building both strength and muscle mass quickly.
Give high rep partial training a try in your next workout and don't be afraid to push yourself. You may be surprised at how many reps you can do with a weight you may not have even considered using before!