Work-to-rest ratio

Work-to-rest ratio compares the duration of an exercise effort with the recovery period that follows.^{1National Strength and Conditioning Association, NSCA’s Basics of Strength and Conditioning Manual, p. 63.} A 5-second drill followed by 50 seconds of recovery has a 1:10 ratio.^{1National Strength and Conditioning Association, NSCA’s Basics of Strength and Conditioning Manual, p. 63.} Interval training uses predetermined work and rest periods.^{2Haff and Triplett (eds.), Essentials of Strength Training and Conditioning, 4th ed., p. 75.}

The ratio depends on which energy system the effort taxes.^{3Haff and Triplett (eds.), Essentials of Strength Training and Conditioning, 4th ed., p. 76.} After a maximal effort depletes creatine phosphate, full resynthesis can take up to 8 minutes, so short, intense efforts need more rest relative to work than longer, lower-intensity efforts.^{3Haff and Triplett (eds.), Essentials of Strength Training and Conditioning, 4th ed., p. 76.}

The NSCA suggests these work-to-rest ratios:^{3Haff and Triplett (eds.), Essentials of Strength Training and Conditioning, 4th ed., p. 76.}

• 1:12 to 1:20 for 5 to 10 seconds near maximal power.^{3Haff and Triplett (eds.), Essentials of Strength Training and Conditioning, 4th ed., p. 76.}
• 1:3 to 1:5 for 15 to 30 seconds of work.^{3Haff and Triplett (eds.), Essentials of Strength Training and Conditioning, 4th ed., p. 76.}
• 1:3 to 1:4 for 1 to 3 minutes of work.^{3Haff and Triplett (eds.), Essentials of Strength Training and Conditioning, 4th ed., p. 76.}
• 1:1 to 1:3 for efforts longer than 3 minutes.^{3Haff and Triplett (eds.), Essentials of Strength Training and Conditioning, 4th ed., p. 76.}

The NSCA cautions that more research is needed to confirm optimal ratios.^{3Haff and Triplett (eds.), Essentials of Strength Training and Conditioning, 4th ed., p. 76.}

In practice

For HIIT, the NSCA uses ratios from 1:1 to 1:8 and lengthens rest as the client tires; going beyond 1:8 reduces the high-intensity work possible in a fixed session.^{4Schoenfeld and Snarr (eds.), NSCA’s Essentials of Personal Training, 3rd ed., p. 455.}

For speed drills, the NSCA gives 1:5 to 1:10, with more rest for higher-intensity drills.^{5Schoenfeld and Snarr (eds.), NSCA’s Essentials of Personal Training, 3rd ed., p. 483.} Its program design guide gives 1:4 to 1:6 for agility drills and says ratios as large as 1:20 are not uncommon.^{6Hoffman, NSCA’s Guide to Program Design, p. 188.}

For aerobic intervals lasting 30 seconds to 5 minutes, rest is usually equal to or shorter than work: 1:1 or 2:1.^{7Hoffman, NSCA’s Guide to Program Design, p. 159.} Sport-specific conditioning can follow game timing; American football plays last about 5 seconds with 25 to 30 seconds between them.^{8Hoffman, NSCA’s Guide to Program Design, p. 141.}