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By Duston Morris, Ph.D., M.S., ACE, USAT

With the obesity epidemic at the forefront of media attention, it is not surprising that multisport athletes are more concerned with weight-related issues than ever before. Years of coaching experience has provided clear insight that one of the target objectives of many people who adopt a multisport lifestyle is to lose weight and improve their overall fitness. But is there a limit to multisport athletes’ weight loss? The answer is yes. I have worked with many athletes who lose considerable weight (50+ pounds) during their transformation into a multisport athlete. During this initial weight loss phase most people see significant performance improvements. The combination of weight loss, increase in strength and endurance typically results in overall improvements for the athlete.

However, the key for most multisport athletes is to help them recognize their peak performance weight. Many multisport athletes become stuck on weight watching. They become overly concerned with what they weigh and neglect obvious signs that can help them determine the weight at which they can obtain maximum performance. The hard part with all of this is trying to determine your ideal body weight. My experience leads me to using simple, but effective measures to help a multisport athlete reach their ideal performance weight.

BMI, or body mass index is a number calculated from a person's weight and height. Generally, BMI is an indicator used by coaches, trainers, and physicians to determine body fatness and is used to screen for weight categories that may lead to health problems. However I believe that BMI can also be used to help multisport athletes determine a weight based performance range. Here’s how:

1. Calculate your current BMI using one of the following formulas:
Formula: weight (kg) / [height (m)]2 – kilograms and/or meters
Formula: weight (lb) / [height (in)]2 x 703 – pounds and inches

2. Determine if your calculated BMI falls within a normal weight range.
< 18.5 – (underweight) athletes should focus on strength training and proper diet to increase weight by increasing lean tissue.
18.5 – 24.9 – (normal weight) athletes should focus on staying within this range by monitoring diet and maintaining regular training program.
25.0 – 29.9 – (overweight) athletes should focus on a healthy diet with correct portion in addition to regular training in order to achieve normal weight.
> 30.0 – (obese) athletes should focus on a structured plan that helps create behavior change which can lead to healthy weight patterns.

3. Once you achieve a BMI within 18.5 – 24.9 use the weight range table that corresponds to your height (see the attached table).
Example: 6’ male with a 21.0 BMI = 154lbs
Example: 5’ 5” female with 21.0 BMI = 126lbs
 
4. Continued weight loss after your achieve a BMI within 18.5 – 24.9 should be monitored carefully.

Once an athlete has reached the recommended BMI range, additional weight loss s could impact their overall performance. If athletes choose to continue with weight loss once they reach the recommended weight range for their height (i.e. go from a BMI of 24.0 to a BMI of 21.0), they should do so carefully and monitor how additional weight loss may be impacting their performance. The general consensus is that a weight reduction of 5-10% can impact performance, but the big question is a 5-10% reduction from what weight?

For example, if I am working with a male who is 6’ tall and currently weighs 195lbs, a 5-10% weight reduction would most likely improve his performance. On the other hand, if I am working with a 6’ tall male who is already within the normal BMI range (let’s say BMI of 21.0 = 154lbs), a 5-10% weight reduction is much more likely to decrease his performance. This is why I recommend using the BMI weight range table to help determine weight based performance.

So how do we know if weight loss is contributing to decrease performance? This can be really hard to determine because of so many other factors, such as diet, sleep, stress, illness. But if all things seem to be normal here are just a few things to help you determine if weight loss might be impacting your performance.
Unusually high training HR, resting HR, or time it takes to achieve recovery HR.
Decreased performance – especially related to extended duration training/racing
Chronic fatigue – no “peppiness” or fitness rebound in the body or legs after a good WO.

If you are experiencing any of the above problems (or maybe others) try to rule out the other factors that could also impact performance. Once you have done this, if performance does not improve add some weight back to your body. I recommend about a 5lb weight increase. See if this helps you get back to optimal performance. Remember that multisport can help us achieve a healthy body, but there is and always will be points of diminishing returns. Participation in multisport is not about weight loss, it is about the personal challenge of overcoming significant physical feats. To do this, each athlete needs to be at a body weight that will produce maximum physical performance, and this weight is not determined by some arbitrary marker like clothes size, popular magazine covers, or desire for the “perfect body.” Multisport athletes need to maintain a strong healthy weight to achieve their goals, but also should strive to maintain a healthy body.