Saturday, 20 October 2012

Anatomy of a pull up (and how to do your first one)

Have you ever tried and failed to do one single pull up, or would you like to better understand the performance factors at work for common bodyweight exercises? Luckily, help is at hand.

Even though I am going to use a specific example here (how to achieve your first pull up), the following principles will generally apply to all strength-based exercises, and the concepts discussed should be easily transferable to other pulling and pushing actions.

Essentially, there are 5 factors affecting your ability to do a pull up (and other common bodyweight exercises). These are:

1.       The stretch-shortening cycle
2.       The nervous system recruitment of prime movers
3.       Muscle hypertrophy
4.       Correct form
5.       Your power to weight ratio

Let’s examine each of these individually.

1.       Try this experiment: bend your legs and, from this static position, try to jump vertically as high as you can. Now repeat the experiment by lowering yourself quickly into the bent-leg position, then explosively ‘bounce up’ into the jump. You should find that the second method resulted in far better performance: this is because of a process known as the stretch-shortening cycle. Essentially, it is well known that a muscle can yield more strength when it has just been pre-stretched. Thus, if you are close to managing a pull up, but need that little bit of impetus, start by lowering yourself from a high position on the bar, then ‘bounce’ into the pull up prior to your arms being fully extended (going down all the way into a dead hang position, rather than keeping a slight bend in your elbows, might prevent you from exploding back up quickly enough to benefit from the process). Pull ups are far easier to perform when you are ‘pumping’ them than when you rest in the dead hang position between each rep. Of course, this will certainly seem contrary to a lot of advice that is usually given on how to perform the move through its whole range of motion. Bear in mind however, that we are not trying to maximise the training effect on the latissimus dorsi here, but rather to get past what is a common sticking point (the initial pull from the dead hang position). As time goes by, you will undeniably get a better workout from lowering yourself all the way ; initially though, get past your sticking point by using the stretch-shortening cycle to your advantage!

2.       A gain in strength, is not necessarily the result of a gain in muscle size or quality. This is particularly true for the first few months of training a new movement: initial gains are largely the product of the nervous system’s increased efficiency in recruiting prime movers. In the initial training stages, the nervous system undergoes an adaptation process whereby it recruits an increasing amount of motor units and fibres, resulting in increased performance. This in itself cannot easily be exploited to increase your ability to do pull ups but, it must be noted that there are subtle differences between apparently similar exercises in the sequence of muscular recruitment. For instance, if your idea of training for pull ups is to perform lat pulldowns on the cable machine, you are probably not getting the most benefits from your training. Whilst lat pulldowns will benefit you from a muscular hypertrophy point of view, the sequence of muscular contractions recruited by the exercise is somewhat different from the pull up. Lat pulldowns are what is commonly known as an open kinetic chain exercise: one in which the distal segment (your arms) is not fixed to an immoveable object (the bar). This differs significantly from the pull up: a closed kinetic chain exercise where the distal segment (your arms) is anchored to an immoveable bar. Thus, in order to train pull ups, build up to the exercise by performing increasingly harder variations and following a pull up progression. Alternatively, resistance bands or an assisted pull ups station also provide a better alternative than the often recommended lat pulldown: increasing your muscle size is simply not efficient enough, though it might be sufficient.

3.       Muscle hypertrophy. Muscle hypertrophy is certainly one of the main components of muscular strength, and the strength necessary to execute your first pull up is best developed at first by developing type IIb, fast twitch muscular fibre. This is generally thought be best achieved by performing repetitions in the range of 1-8. As you get stronger, you can start developing your strength endurance by performing repetitions in the range of 8-12, which will also recruit type IIa hybrid fibres. Thus, performing easier variations of the pull up for 4-8 repetitions offers a fast track to achieving your first pull up.

4.       Correct form. Generally, with any exercise, correct form cannot be emphasized enough in training: not only does it help in preventing repetitive strain injuries, it is also a way to maximise efficiency of movement. The problem when it comes to pull ups is that there doesn’t appear to be any consensus as to what proper technique is! One of the points of contention is whether it is preferable to keep your shoulders ‘packed’ (i.e. your scapula retracted down), or whether to allow your shoulders to rise up at the bottom of the movement. A lot of common advice focuses on the former. However, for an alternative view, watch this video by Paul Zaichik, of elasticsteel fame. Beyond questions of shoulder impingement, what is the most efficient technique to perform a pull up? Some recommend arching your back, others keeping it straight ; different hand width and hand positions are also often suggested... Here is my take on the matter: we are all different, and have different muscle group developments. It makes sense for someone who has comparatively well-developed biceps to maximise that strength by using a narrower grip when trying to achieve their first pull up (or even to switch to a supinated hand position and perform chin ups instead). Thus, the most efficient technique for performing pull ups will depend largely on your morphology and muscular development, provided you follow basic biomechanical guidelines. I do find however that it does help to cross your ankles and brace your core as you perform the movement, as this confers you better balance and control through the whole range of motion.

5.       It should be obvious that pretty much all bodyweight exercises are dependent on your power to weight ratio: the lighter you are – your strength being equal – the easier it becomes to perform this type of exercises. However, losing weight is not necessarily always a key factor in improving performance, as there is a degree of diminishing return: if weight loss is accompanied by muscle loss, then performance will often remain the same, if not be affected negatively. Generally speaking though, when it comes to pull ups, lighter is better: take a look at top class gymnasts and climbers, and you should get a good idea of the body type that is most suited to bodyweight exercises.

To summarize:
-          Gradually build up to your first pull up by training easier variations or by using resistance bands.
-          Use the technique and grip that feels the easiest for you.
-          Perform reps in the range of 6-8 to recruit type IIb fast twitch muscle fibre (5 sets of 4-8 reps would generally be considered to be optimal).
-          When you’re getting close to managing your first pull up, start from a high position on the bar, lower yourself down then bounce up explosively to make use of the stretch-shortening cycle.
-          Be mindful of your power to weight ratio. At the very least, try to bring your body fat percentage down (this article will help you with weight loss: weight loss made easy)

1 comment:

  1. Fantastic article. I just got my very first pull up but can't wait to try the stretch shortening technique in my next session. This has been a lesson in patience, determination, and discipline. But mostly patience!