Triathletes need to be in top physical shape to excel, but carrying too much or too little weight will impede your performance. It's hard enough to master three sports--swimming, biking, and running--and improper body weight can make it harder. Carry too much weight on your frame, and your speed and times will suffer. Be below your healthy, competing weight and you will lack the needed musculature and stamina to perform to the best of your ability.
To determine your ideal triathlon competition body weight, identify your body type. According to Body Building Pro, there are three basic body types -- ectomorph, mesomorph, and endomorph. The ectomorph tends to be very lean without much muscle mass, somewhat fragile, and with longer legs and arms. The mesomorph is more of the classic athletic, muscular build with arms, legs and torso well defined and muscled. The endomorphic body is rounder and softer with greater mass focused in the abdominal region, but with well-developed upper arms and thighs. You can be a combination of two or three types.
Diet and Nutrition
Although you may tend toward a certain body type, when you are training for the three sports of triathlon, you soon come to realize the value of the correct diet and nutrition. Most triathletes burn copious amounts of calories during daily training, and as BeginnerTriathlete.com notes, you can eat anything and everything and still stay relatively thin. However, the first law of thermodynamics still applies -- to maintain your weight, calories in must equal calories out. It's simple; eat more than you burn, gain weight; consume fewer calories than you burn, lose weight.
Body Mass index
One indicator of of body weight vs. fat is body mass index, or BMI. According to Sports Fitness Advisor, the formula for this calculation -- in metric measurement -- is BMI=kg/m2, or weight and height squared equal your BMI. The article notes that if your BMI = 18.5 or less, you are underweight, 18.5 to 24.9 is normal weight, 25 to 29.9 is overweight, and 30.0 or more equals obesity. BMI calculation is meant for the general lifestyle of the average person. Triathletes are more likely to have more muscle mass than body fat compared to the average person.
What to Watch For
When weighing in to see if you are at the ideal body weight for tri's, make sure to consider other factors such as strength training. You can gain muscle mass resulting in increased body weight from lifting weights. In his book, "Triathlon 101," John Mora says you should consider dehydration as a danger of too much weight loss. Upon rising in the morning and after urinating, get on the scale. If you have lost 3 percent or more of your body weight it means you have lost too much fluid and too much weight.
Tri Body Specifics
Any and all information -- such as BMI, body types, and nutritional factors -- can help you find your ideal body weight for competing in tri's. You also can use your own intuition and common sense. If you compete in triathlons and do the proper training, your body naturally morphs to it's fittest level. If your times in any of the three sports are not up to snuff, check your body weight, and adjust it up or down for better results.