As we head into the winter months, weight gain is nearly inevitable. On average, Americans will gain between .48 and 2.22 kilograms during the holiday months (Yanovski, et al. 2000). As endurance athletes, we often associate weight gain with holiday season and justify it due to the amount of training we will put in during the spring and summer months.

The point of this blog is to discuss how weight can affect performance in endurance sports for either positive or negative results. This blog will not touch on dietary habits as I am not a registered dietician.  The only purpose of this blog is to make you aware of specific weight principles/theories and how they may contribute to your success or downfall in 2017.

Disclaimer: Regardless of the thoughts in this blog, a healthy BMI (Body Mass Index) is considered between 18.5-24.9. There are both positive and negative side effects to losing or gaining weight that puts you outside of this range. It is up to you, the reader, to understand these principles or consult with a registered dietician for individual success.

When we look at long distance runners or run specific athlete’s, there is no doubt that they tend to carry around less body weight. However, what is the actual purpose of this from a performance aspect? Well, it has been well established in the running community that each pound you lose will make you about 2 seconds per mile faster (generalized concept).

Example of how weight can affect running
Goal: Boston Qualifying
Pace needed: 7:35/mile or faster for a marathon
If we take this generalized idea into account with a 5’11 athlete that weights 186 pounds (BMI is 26) and runs a 8:00 pace for a marathon, this athlete could lose a substantial amount of weight and still be classified as healthy via the BMI scale. Lets suggest that this athlete gets serious about nutrition and loses 30 pounds over the course of a year and is at 166 pounds. This athletes BMI is now around 23, their pace has dropped to 7:00/mile pace, and with the proper training they now have a realistic shot at reaching their Boston Qualifying goal.

Regardless of the athletes goals, if you are above 24.9 in the BMI chart or even in the upper range of the healthy zone, you can still lose some weight to become a faster runner overall. Beyond the faster speeds, you will be reducing the impact on your legs with each stride and you will be able to handle a higher training load if built correctly.

Note: There is a point where you can be too light for optimized performance. When your body can’t respond to the training load and you are constantly becoming hurt, it could be an indicator of a poor diet or lack of muscle/bone density to help absorb the miles of running.  This is very personalized and therefore you should not make any specific plans simply off this blog alone.

Weight in cycling is one of the largest factors of success that often gets neglected at the amateur level. Depending on your strengths and the terrain of the race, weight will make all the difference between winning an event or finishing mid-pack without a chance. What many amateur cyclists neglect is race selection based on their strengths. While I understand wanting to race often and I see great value in that, expectations in cycling should be catered around race selection and which race fits your watts/kilogram chart the best.

Example of how weight can affect cycling performance
Let’s look at Fabian Cancellera vs Nairo Quintana. Fabian Cancellera has an unbelievable amount of raw watts he can sustain for long periods of time. His actual power numbers would destroy Nairo’s numbers if they were compared as apples to apples. However, due to Nairo weighing 40 lbs less than Fabian, there is no way that Fabian can stay with Nairo as soon as weight starts becoming a factor (the terrain increases). Therefore, because of how big of a factor weight can be in cycling performance, each of these professionals targets races that work into their strength (Fabian = 1 day classics and TT’s, Nairo = grand tours with mountain climbs).

While we aren’t Fabian Cancellera or Nairo Quintana, we all have our own strengths and weaknesses in the cycling world due to weight and genetics. By testing where you are in the watts/kilogram chart (developed by Andrew Coggan), you can begin to see what type of races you should be targeting and how losing or gaining weight may help in your overall performance.

Note: If an athlete is racing in flat terrain and has a strong bike set up, they may actually benefit from gaining weight which will generate a larger overall amount of watts. On flat ground with higher watts and a strong bike setup, you can actually improve your performance by gaining weight (see track cyclists for example).

I don’t want to spend too much time on this as swimming performance revolves around technique and experience much more than weight. However, I will touch on two aspects of swimming and how weight is factored in.

First, swimmers tend to develop a small layer of fat over their bodies for two reasons. The first reason is that swimming pools tend to be a bit cold when used for training. Swimmers will actually develop a small layer of fat to help insulate their cores and bodies.  Secondly, the small layer of fat can act to help create some buoyancy. This buoyancy will help keep the body high in the water for reduced drag (think wetsuit).  Now, with that being said am I telling swimmers to gain weight… no. I’m just discussing what tends to happen with swimmers bodies. They tend to be very fit and strong, they just don’t have the chiseled physique of other athletes.

Where weight can hurt swimming though is due to the amount of drag created by the overall size of body mass. So, if you don’t have proper technique and you have pounds to lose, you are actually having to pull your body through a large amount of water with each stroke. The thinner you get the smaller the amount of drag you will produce as long as you keep the same efficiency in the water.

As the races get longer and the sun is beating down on you, body mass will start to play a large role in the overall performance. For Triathletes that spend 1-17 hours at a race, the longer the race, the more impact weight plays on overall performance. While you can read above the reasons how weight affects each individual sport of triathlon, the one note that I haven’t touched on is heat dissipation. Due to Triathlons often taking place in the hot summer months of the year, heat dissipation will separate the great from the good in the triathlon world.

When looking at elite performance in the sport of triathlon, the number that always comes out of the mix is a BMI of an athlete between 20-22. While each athlete will get their in different ways, this amount of body mass allows them to be a fast runner, produce the power/weight needed for the bike, swim efficiently, and shed heat in a more effective manner than say a triathlete at 23-24 BMI. Due to heat being such a large factor on race day, the better your body is at cooling, the faster you will be.  With mass being the key ingredient in how fast your body cools down, it can therefore be linked with race day performance.

A note on BMI
There are far better metrics to use for athletic performance than BMI. This blog only serves as a generalized standard that can be used from a Bird’s Eye view. Athletic performance should be looked at through each specific sport and key factors. Therefore, you can use BMI as a general gauge, but again, each athlete is different and don’t use BMI as your only mode of gauging performance.

The purpose of this blog was to show how weight can be an overall factor in athletic performance. While there are plenty of numbers being thrown around in this blog, don’t settle on the mindset that lower weight always equals better performance. While lower weight often does create a better performance, there is a point of diminishing returns. By being educated on what the numbers mean and finding where you produce the best results, you are in a far better place to set realistic goals and achieve them.