Racepack / Backpack Basics

March 23, 2014


At first I thought about writing an article to compare various race-packs but decided against that for one simple reason; such an article would represent my personal preferences which may be very different from the preferences of others. I, therefore, decided to rather write an article that would enable my readers to (1) select the best possible race pack for themselves, and (2) to use that race pack correctly. The latter point may be more relevant to the MdS runners who, with only 11-days to go until their epic adventure, are deciding what to pack and where to put it in their packs.


Basic Mechanics

As bipedal beings we have to ensure that our bodies remain in a balanced state to ensure, not only, that we remain upright, but also that we spend our energy efficiently. Energy efficiency is a key component in any ultra-endurance event and the aim should always be to be as efficient as possible.


Bipedal motion in humans centres on their hips with the balance point or more accurately named, our centre of gravity, being centred around the sacrum which is a triangular bone located at the bottom of the spine. This hypothetical point, however, is not fixed and is adjusted in-terms of form, weight etc. Example, a pregnant woman would carry more weight in-front of her moving the centre of gravity forward. To counteract the effect of imbalance she would lean backwards. So we use posture alignment to accommodate for imbalance and to create some form of balance while in motion.


The same principle applies to carrying a backpack or race pack. But there are other factors that play a very important role. For instance, when you take a ruler and place a weight on one end you need to move your finger closer to the weight to ensure that the ruler remains in a balanced state. Your alternative would be to load the opposite side of the ruler with a weight as well. Depending upon the two weights at opposite ends you would adjust the centre of gravity of the ruler finding the balanced point somewhere between the two points.


Selecting a Racepack / Backpack

So what has this got to do with selecting a racepack or backpack?


In short, everything, the aim of a racepack or backpack is not simply to fulfil the function of carrying all your items, but rather to carry it in such a way that the weight does not have a significantly detrimental effect on your performance. The following four points, I consider to be critical:


  1. Hip Strap: Your hips serves as the point around which your ‘balance’ and motion is centred and represents a strong anchoring point for any weight you carry. So selecting a bag that will fit your body length is essential. The hip band or strap must sit on your hips; the aim is to rest 80% to 90% of the total pack weight on your hips. 

  2. Shoulder Straps: These should be comfortable, broad, and well-padded to prevent the straps from cutting into you. If the pack is correctly matched to your body length and the hip belt sits on your hips and not your abdomen the angle of the shoulder straps leading to the bottom of your pack won’t cause chaffing, however, if the pack is to short the shoulder belt will be pulled tight under the arm which may cause chafing. Shoulder belts should allow you some freedom of ‘alteration’ so that you can make adjustments specific to you, add water bottle holders (if you wish) and have the ability to alter the height of the chest or sternum strap. A really helpful, but not vital, addition is that of load-lifter straps. Many runners don’t know about load-lifter straps and I have seen these either not used, used incorrectly or altered to the point that they lose their purpose. Load-lifter straps are located just below the tops of your shoulders (near your collarbones) and are intended to pull your shoulder straps backwards and upwards to relieve the pressure off your collarbone. 

  3. Pack Compartmentalisation: This is essential as where you carry your weight in the pack is critical. The closer you can pull the heaviest items towards your back the will mean that your centre of gravity will move slightly back requiring less forward leaning to remain in balance. The old idea of carrying your weight in the bottom of your pack has been challenged in recent studies and has been proven not to be an optimal way of carrying your pack. Depending on your anticipated terrain your highest weight will either be in the middle of your back or towards the top of your pack and always close to your back. The following link provides some images and brief explanations: Click Here It is, therefore, vitally important that you can secure items inside your pack into specific positions, and that they would stay there until you chose to move them. 

  4. Back to Front Weight Distribution: Another great option is the ability to add a front pouch as a means of (a) distributing the weight and (b) providing an easily accessible storage for items you may need during the day. Having this available eliminates the need to take the pack off multiple times during the day. This, however, speaks primarily to personal preference. A bouncing front pack could be irritating and even cause abdominal cramps so not only is this personal preference but you should run with this configuration regularly during training, especially on your long-runs to see how this impacts on you personally. 

  5. Trust: One of the most overlooked aspects is that of trust between runner and pack. If you look at your pack and is unconvinced that it will do what you need it to do, you will not have the confidence to use it correctly. I, personally, still do not have confidence in ultra-light racepacks (and yes I have the photos to show how I have had to repair torn material – because of weight and movement). So I have an ultra-light race pack that weighs around 650g but then packs all my items in two light-weight dry bags inside the pack. On-top of that I also carry items with which to repair my bag (yes I have had to do that out in a race before as well). So my ultra-light racepack is now no longer so ultra-light as the additional risk mitigation I deploy weighs in at around 350g to 400g. So now my actual ‘racepack’ weighs in the order of 1 to 1,1kg’s. Now I don’t mean to say that you shouldn’t buy and use ultra-light racepacks, but rather, that you should buy the product that you will have the greatest confidence in. Weight is outweighed by personal confidence and trust.


Carrying a Racepack / Backpack


There is a four step process to correctly adjust your race pack:


  1. Tighten the hip belt to secure the pack on your hips,

  2. Pull your shoulder straps tightly so that the weight of the pack is pulled towards your back. This is all the shoulder straps must do. Remember your hips carry the weight; your shoulders keep the pack upright and its weight close to your back.

  3. Adjust the load lifters to relieve the pressure on your collarbone and shoulders, but not so much that the pack is pulled away from your shoulders as this will cause neck strain.

  4. Adjust the chest / sternum strap. The aim of this is to slightly pull the shoulder straps towards the centre of your chest to allow your arms to move freely.


I hope this helps those of you who still need to buy a race or backpack in selecting that which is appropriate and best suited for you. I also hope that this posting will help all of you to pack and carry your race pack more efficiently going forward.


Thank you for reading these posts.


Genis and the push2extream team.

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