Running and weight
You know the direct relationship between running and losing weight, that is the most common relation people make. But running with less weight on you will also help your efficiency, mechanics, keep your temperature down, and will keep injuries at bay.
Several studies have shown runners dropping up to 2.4 seconds per mile for every pound of weight lost (1.5sec/km for every 450gr). This means that losing 10 pounds (4.5kg) will shave an extra 15sec/km. If you put the numbers in, a 50min 10k suddenly turns into a 47:30. And you will go from 3:31hr to 3:20hr in a marathon.
Think about it, if your VO2 max is 50ml/kg/min, the easiest way to increase it is to reduce the kg in that equation and maintaining everything else as is.
Another important perk of losing weight for runners is the reduced risk of injury. No matter how good the technique, there will always be an impact on the joints and tendons coming from hitting the ground repeatedly over hours at a time. Maintaining a healthy body weight will help reduce this impact, contribute to proper posture, and facilitate mobility.
So, lighter is better and faster, then? Well, kind of, you just need to do it carefully and not expect miracles. You can't just go on a crash diet and expect to perform well. There is such a thing as a perfect racing weight where you have enough muscle mass to deal with the impact of your event. If lighter were always faster, Usain bolt would be a feather. Instead he is close to 100kg of just muscle because his event requires dealing with several times his body mass to be caught, stabilized and redirected for a few seconds. A champion marathoner also deals with high amounts of weight to be directed through the muscles, but running at roughly half the speed of a sprinter means less weight over more repetitions, so the muscles are different. In the end, both athletes will deal with insane amounts of force, what changes is the fibers needed for each type of impact.
For amateur runners, most weight loss will come from fat. This means that getting close to our ideal weight could be just going from 30% body fat percentage to just 20% or go in for the six-pack with 12%.
Here are some things you need to know to achieve this:
1) Running slow and easy is not the best way to burn fat. This one is a little complicated. Zone 2 is the fat burning zone, but you also need to make this zone faster to burn more. Most recreational runners will be better served to work on their speed and power first with some HIIT training and progressively increase their long steady runs in a way that they get faster over time. Calories burned are a direct result of work done.
2) Take it easy on the wight loss. Reducing caloric intake by more than 500kcal per day can be dangerous and will affect performance. Aim for slow, steady, and sustainable weight loss instead of an emergency drop. Start today, but don't try fixing years of bad habits over a few weeks.
3) Losing some muscle mass is OK. If you are an endurance athlete, especially when it comes to arms, chest, and back, some of the heavier muscles will have to go. Don’t worry, looking skinny like an elite marathoner takes several years of 30+ hours per week of training, you are most likely in no danger of looking like one.
So, now you know. The easiest way to get faster for most amateur athletes today is dropping some pounds. And of course, the training required to do so will also add to your speed, so it is a double benefit. This obviously works just as good for cycling, especially when climbing.
Before investing on the latest shoes with springs, the most aero bike ever, or any McGuffin gadget promising speed, just consult a nutritionist and get some free speed just by fitting in to your old jeans!
Hope this article helps. It's been a long couple of weeks with everything going on, but I will get some more in-depth articles soon enough.
In the meantime, stay healthy, eat well, run fast, and go strong!
Coach OM