Energy requirements of strength and power athletes

Strength and power athletes typically have to develop and maintain excessive body mass (especially lean mass) and also extreme strength and power. Thus, sound dietary practices are just as important as proper training practices. There are three components to consider in regard to the energy requirements of these athletes.

1.      Daily energy requirement

This is determined by three factors which are the basal metabolic rate (BMR), physical activity and the thermic effect of food. According to Wilmore and Costil (2001) as cited in Antonio (2008), of these three factors, BMR accounts for about 60-70% of the total daily calories. This is followed by physical activity which is the most variable factor. The least significant factor is thermic effect of food which refers to the amount of calories required to digest and absorb the consumed foods.

The Harris-Benedict equations (Harris and Benedict, 1919 as cited in Antonio, 2008) are most frequently used to calculate BMR or more practically, resting metabolic rate (RMR) instead.

Males: BMR (calories/day) = 66.5 + (13.75 x weight in kg) + (5.003 x height in cm) – (6.775 x age in years)

Females: BMR (calories/day) = 655.1 + (9.5663 x weight in kg) + (1.85 x height in cm) – (4.676 x age in years)

This will provide us with the minimum amount of daily calories required by a person at rest. However, we need to also consider their daily physical activity level (PAL) to calculate their daily energy expenditure and thus their minimum daily calorie requirement. We have to multiply the RMR by a PAL factor that best resembles them. Table 1 below shows the various PAL factors.

Table 1: Physical activity level factors

Activity factor	Activity level
1.53	Sedentary or light activity
1.76	Active or moderately active
2.25	Vigorous active

Example: I am 170 cm in height and 62 kg in weight. I would consider myself to be active. Thus my PAL factor is 1.76.

Calculations: BMR (calories/day) = 66.5 + (13.75 x 62) + (5.003 x 170) – (6.775 x 32)
                                                 = 1553 calories/day
Minimal daily calories requirement = 1553 x 1.76
                                                      = 2733 calories

2.      Body weight goals

If the athlete needs to increase or decrease body mass, we need to adjust the daily calorie intake to be above or below the minimal daily calories requirement. One pound of body fat is about 3500 calories. For weight/fat loss, the athlete should ingest 500 calories lesser daily which would allow him/her to lose one pound of fat per week.

One pound of muscle is about 2500 calories. So for muscle gains, the athlete should ingest about 300-500 calories more daily. It is recommended that the athlete eat about 4-6 meals per day in order to meet this required intake.

3.      Macronutrient needs

Once these two factors are addressed, we need to consider the issue of macronutrient intake. Most strength/power athletes should get 12-15% of their calories from protein, 55-60% from carbohydrates and 30% from fats (<10% from saturated fats) (Kreider and Almada, 2004 as cited in Antonio, 2008)

References:

Antonio, J., Kalman, D., Stout, J. R., Greenwood, M., Willoughby, D. S., & Haff, G. G. (Eds.). (2008). Nutritional needs of strength/power athletes. In A. Stopppani, J, Scheett, T.P. and Mcguigan, M.R. (Eds.),  Essentials of sports nutrition and supplements (pp. 350-352). Chapter Humana Press.

Harris, J. S., & Benedict, F. G. (1919). A Biometric Study of Basal Metabolism in Man (Carnegie Institution of Washington publication# 279). Washington, DC: Carnegie Institute.

Kreider, R. B., Almada, A. L., Antonio, J., Broeder, C., Earnest, C., Greenwood, M., & Ziegenfuss, T. N. (2004). ISSN exercise & sport nutrition review: research & recommendations. Sports Nutr Rev J, 1(1), 1-44.

Wilmore JH, Costill DL. Metabolism, energy, and the basic energy systems. In: Physiology of Sport and Exercise. 3rd ed. Champaign, IL: Human Kinetics Publishers; 2001: 139