The Navy SEAL Physical Fitness Guide - Human Performance

The Navy SEAL Physical Fitness Guide 51

Watts, as stated above, are units used to quantify the rate of doing work, or work/

time. Most new exercise equipment express work rate in terms of watts, although many use

METS instead of or as well as watts. Table 3-13 presents the relationship between various

terms denoting exercise intensity. These can be used to monitor exercise intensity.

Summary

No doubt new modes of exercise will be appearing in the future. What you chose to

use will depend on many factors. The important issue is whether you are able to achieve the

desired work rate and conditioning level. A recent study of indoor exercise machines

examined energy expenditure at given ratings of perceived exertion. They compared a

treadmill, a rowing ergometer, a combination cycle/arm ergometer, a cycle ergometer, a

stairstepper and a skiing machine. Surprisingly they found that rates of energy expenditure

varied by as much as 261 kcal/hour for the exercise machines when subjects exercised at

self-selected work rates corresponding to fairly light, somewhat hard, and hard. The

treadmill came out with the greatest energy expenditures, followed by the rowing and

stairstepping ergometers; the cycle and combination cycle/arm ergometers came out with

the lowest values. If exercise intensity is established by perceived effort, treadmill running/

walking will result in greater energy expenditure and a stronger cardiorespiratory training

stimulus for a given duration of exercise as compared to other modalities.

Table 3-13. Workload Conversion Sheet

Watts

Oxygen

Uptake

(L/min)

Work Rate

Energy

Output

(kcal/hr)

METS

50 0.9 Easy 270 4.0

100 1.5 Fairly Easy 450 6.7

150 2.1 Moderate 630 9.3

200 2.8 Moderately Hard 840 12.4

250 3.5 Very Hard 1050 15.5

300 4.2 Very, Very Hard 1260 18.7