February 24, 2013

Find Out What May Be Limiting You From Making The Progress You Want To Make


In the book, Science and Practice of Strength Training, the authors write “The heaviest weight that is lifted through a full range of motion cannot be greater than the strength at the weakest point”, meaning that one is limited to how much weight they can lift by the amount of strength that they have at the most disadvantageous position of a lift.

Advantageous vs. Disadvantageous

The most advantageous position of a lift is the one where the least amount of effort/strength is needed to lift a given weight. Therefore, the most disadvantageous position of a lift is the one where the greatest amount of effort/strength is needed to lift that same amount of weight. Generally the most advantageous point of a lift is when the prime movers are in a shortened state, and the most disadvantageous point is when the prime movers are in a lengthened/stretched state, and if one wants to increase their 1 rep max (1RM), they need to increase the amount of weight that they can lift in the most disadvantageous position of a lift.

While it is accurate to say that one is limited to how much weight they can lift by how strong they are at the weakest point of the range of motion, it is incomplete by not accounting for (metabolic) fatigue, which accumulates the longer the time under tension, and can influence just where that weakest point is.

The Limiting Factor Principle As It Relates To Time Under Tension

The longer a muscle, or group of muscles, is under tension for, the more it will become a limiting factor.

Exercises are generally looked at in terms of which muscle groups they are ‘supposed’ to target. But, what a lot of people fail to realize is that, just because an exercise is supposed to target a specific area, does not mean it is limited to that area only, even if it is an ‘isolation’ exercise, as the all the muscles of the body work in unison to perform a given task (some more so than others, obviously, depending on that task). Only when you breakdown a movement, and consider what other muscle groups are indirectly, but highly involved, do you begin to see what will ultimately become a limiting factor the longer a set, or workout, goes on.

The muscle(s) that are under constant tension during the course of a set are the ones that will become a limiting factor either acutely (during that set) or chronically (during the workout, or from one workout to the next), so it’s important to know what those muscles are so you can program accordingly to get the best return per investment of time/effort.

Single-Joint vs. Multi-Joint

With most single joint exercises, the limiting factor will almost always be the primary muscle group being trained, since it will be the one placed under the most amount of tension. There are instances though, when a muscle group that isn’t being directly trained will be the limiting factor.

Multi joint exercises on the other hand involve an assortment of muscle groups to a much greater degree, which means you may in fact be limited by muscle groups that aren’t ‘supposed’ to be worked with that specific exercise.

The Most Common Limiting Factors That Affect Performance

The Lower Back

Any axial loaded movement not only compresses the spine, but requires the lower back to maintain continuous tension just to keep you erect/upright (hence the name of the muscles responsible for this being called the erectors). Therefore, fatigue of the lower back due to constantly being engaged during a set could ultimately affect ones performance during exercises like squats, lunges, split squats, step-ups (which are movements no one would prioritize if their goal was specifically to strengthen their lower back).

Squats, Lunges, Split Squats, Step-Ups

If one chooses to perform a squat, lunge, split squat, or step-up, it’s likely that they do so with the goal of targeting the quads, glutes, and hamstrings.
As far as the most advantageous and disadvantageous positions are concerned, the most advantageous would be when the knees, hips, and ankles, are optimally extended and the individual is standing erect, and the most disadvantageous is that in which the knees, hips, and ankles are optimally flexed. Therefore, in these cases one is limited to how much weight they can attempt to lift for one rep by how strong their quads, glutes, and hamstrings are in their most disadvantageous (stretched/extended) position.

However, if one was to perform a set of 20+ reps in a set, or even a high volume workout in which you performed 10 sets of 10, fatigue would alter what the limiting factor is.

With squats, lunges, split squats, and step-ups, you can choose to deliberately keep tension on the targeted muscles by performing your reps rhythmically, in a ‘pumping’ fashion, until lactic acid accumulates within the muscles to the point that it impairs their ability to contract, in which case tension must be temporarily removed to allow for the metabolic waste to flush out of the muscle so it can continue contracting.

The two ways this tension can be removed to allow the muscles to immediately regenerate ATP is by simply ending the set, or for those who want to get as many reps as possible by any means necessary, do what most people do (whether they realize it or not), and remain as upright as possible for a few seconds with the bar resting on your back. When the knees, and hips, are extended at the top of a squat/lunge/split squat/step-up, the tension in the quads, glutes, and hamstrings is dramatically reduced, which allows for the instantaneous replenishment of ATP for those muscle groups.

The erectors of the lower back however, don’t have the luxury of relaxing between reps to allow for ATP to be replenished, as they have to remain under constant tension just to keep you from falling on your face with a loaded barbell on your back. This ongoing tension leads to the accumulation of metabolic waste, ultimately impairing muscle function/contraction.

On top of that, with uni-lateral exercises like lunges, split squats, and step-ups, the lower back is doing double the amount of work with each set. While each leg has the opportunity to rest while the other leg is working, the lower back has to remain engaged for the entire duration of the set.

By taking into consideration that the lower back can very often become a limiting factor with axial loaded movements, especially as the volume is increased, you can effectively plan your workouts, and warm-ups, accordingly. If your lower back is limiting how much weight you can lift for exercises that are specifically designed to target other muscle groups, it will be a daunting task to make improvements in those exercises.

The Arms (Triceps and Biceps)

Pretty much every single upper body exercise can be classified under one of two categories:

A) Pushing/Pressing

B) Pulling

Regardless of whether you are pushing/pressing, or pulling, or if the exercise is a single joint, or multi joint movement, the weight that you are lifting is transferred through the elbow joint on its way to the intended muscle group that attaches in the shoulder joint. Therefore, if the muscles responsible for extending (triceps), and flexing (biceps, brachialis, etc.) the elbow are not strong enough to provide the force, or stability, necessary to handle the weights that the larger muscles of the torso (pec, lats, etc.) are capable of handling, you will be limited to how much weight you can attempt to lift.

With both pushing/pressing, and pulling movements, the most advantageous position is when the elbow is optimally extended, and the most disadvantageous position is when the elbow is optimally flexed. The greater the bend in the elbow, the more force that is required to move a given weight, but the greater extension in the elbow, the less force that is required to move the same amount of weight. Therefore, one is limited to how much weight they can attempt to lift for one rep by how strong their pecs, lats, delts, etc, are in their most disadvantageous (stretched/extended) position. This holds true for nearly all upper body movements.

For example, with both the bench press and the pull-up, a much greater amount of weight can be used to perform only the first ¼ of the movements range of motion in which the arms go from fully extended, or locked out, to minimally flexed, but a greater amount of force is required to press that same amount of weight off the chest, or lift the same amount of weight up till your chin clears the bar. In both cases, the amount of force required increases in direct proportion to increases in the range of motion.

However, as with the example above regarding the lower back, if one was to perform a set of 20+ reps in a set, or even a high volume workout in which you performed 10 sets of 10, fatigue would once again, alter what the limiting factor is.

Muscles are gradually smaller and weaker by comparison, the further away from the midline of the body that they’re located. Logic would then dictate that the relatively smaller muscles are subject to greater levels of fatigue per repetition performed. In the case of the bench press, and the pull-up, because the tension passes through the elbow joint on its way to the shoulder joint, the muscles responsible for extending, or flexing the elbow, are likely to become ones limiting factor, the more reps they choose to perform. Whether they realize it or not, this is why lifters have difficulty locking out the elbows to rack the bar at the end of a set of bench presses, and why they can’t pull themselves all the way up to the bar at the end of a set of pull-ups.

By taking into consideration that the muscles responsible for extending, and flexing the elbow, can very often become a limiting factor with pretty much every single upper body exercise, especially as the volume is increased, you can effectively plan your workouts, and warm-ups, accordingly. If your triceps or biceps are limiting your ability to complete reps through a full range of motion, your results will be compromised while the risk of injury is elevated.

Grip Strength

Grip strength is a no brainer as far as limiting factors are concerned in that, if one cannot hold onto weight, then nothing can be done with it. This doesn’t apply to pushing/pressing movements as much as it does to pulling, because with pushing/pressing movements the weight simply needs to be supported by the hand, whereas with pulling movements the hand needs to be tightly clasped around the weight.

Because the muscles of the hand are as far away from the midline of the body as can be, they are the smallest muscles from a relative perspective, that are heavily involved in most upper body movements in which the weight needs to be held tight by the hands, and therefore the first to fatigue. Very often a lifter will fail during a high volume set/workout of deadlifts, pull-ups, etc, because their grip ‘gives out’ before the primary muscle group(s).

This is the sole purpose for wrist straps having been created. The straps enable a lifter to strap weights to their arms that they otherwise wouldn’t be able to hold onto, so they can direct greater levels of tension onto the primary muscle group(s). The use of straps however, will come at the expense of one’s grip strength, as the muscles responsible for gripping don’t need to create much tension at all if an external piece of material is doing the work, and therefore have no need to adapt by getting stronger.

Combine all this with the fact that the muscles responsible for gripping a weight are called upon every single time you pick something up, and not just in the gym, and it’s easy to see how grip strength can easily become a limiting factor.

Warm-Up

One of the biggest mistakes that most people make is performing too many warm-up sets/reps before using their working weight. The purpose of a warm-up is to rehearse the movement pattern, and pump a little blood into the primary musculature to warm it up (hence the term ‘warm-up’), not to fully exhaust the smaller muscles that become limiting factors as the volume placed upon them increases. Very often people will wonder why they have not been able to make progress, and why their strength levels aren’t going up, without taking into consideration that by the time they attempt to break a personal record, they’ve already lifted several thousand pounds!

An effective way to warm up that is sure to have a positive impact on performance, without exhausting the most common limiting factors talked about throughout this article, is to ‘overreach’ during the warm-up. For example, on your way up to your working weight, you actually attempt to lift more than your working weight for one rep, to reap the benefits of what is called ‘post-tetanic facilitation’. That way, when you move onto your working weight, it will feel lighter by contrast.

Training Split

Which muscle groups are worked or which days can indirectly affect performance as well. Using the examples above, if one were to do a high volume back workout, with some direct work for the lower back, and followed that a day or two later with a leg workout, in which they intended to perform one, or multiple, axial loaded movements, the lower back could easily limit the amount of work they could perform.

Performing some direct work for the elbow extensors, flexors, or even some grip work, a day or two before performing a workout in which the muscles responsible for extending, or flexing the elbow, or gripping a weight are of primary importance (presses, pulls, curls, as well as the other examples above) could easily limit the amount of work one could do.

It is for these reasons that knowing which exercises take priority in a routine should dictate which muscle groups are trained on what days. An ill advised training split can not only limit your ability to perform the amount of work necessary to get the best result per time of investment, but can lead to overtraining, and increase the risk of injury.

If you have any questions about limiting factors, and how to identify what may be limiting you, feel free to contact me at ben@paramounttraining.ca. I'm available for online consulting and personalized program design, as well as one on one training if you are located in the Greater Toronto Area (GTA).

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