Rest Periods Between Sets

Recovery, both between sets and between training sessions, is an important factor. The rest periods allowed between sets are determined largely by the goals of the training program (Fleck & Kraemer, 1997).

Rest between sets by goal:

• Strength: if the goal is to increase the ability to exhibit strength, relatively long rest periods (several minutes) should be used. Phosphocreatine, the fuel of the ATP-PC system, comes back in two phases: a fast phase with a half-time of about 21–22 seconds and a slow phase with a half-time of more than 170 seconds (Harris et al. 1976), so near-full recovery takes several minutes. A systematic review of 23 training studies found that trained lifters need rests of more than 2 minutes to maximise strength gains, while 60–120 seconds is enough for untrained people (Grgic et al. 2018).
• Muscular endurance: rest periods of 30 to 60 seconds between sets are sufficient.
• Bodybuilding (historical practice): most bodybuilding routines involve rest intervals of 60 to 90 seconds between sets. That is common practice, not a tested optimum (see the research update below).
• Large muscles (e.g. quadriceps, as in squats): may require rest periods of 3 to 5 minutes.

In the original reference program, a combination rest of 1½ to 2 minutes is used in the COMBO (hypertrophy & strength) program. For strength emphasis, rest is 3–4 minutes; for muscle mass emphasis, rest is 1–2 minutes.

Rest between exercises: depends on the muscle groups exercised that day and the training goal. In a total-body routine, alternating upper/lower body or push/pull exercises lets one body part recuperate while the other works, so the rest between exercises is minimal (e.g. after bench press and before military press, do leg presses to allow recuperation).

Rest and the energy systems (athletic strength training): where rest periods are placed and how long they are determine which energy system is primarily stressed (ATP-PC or lactic acid).

• To stress the ATP-PC system, rest periods should be taken after each exercise and last four minutes or more (practically, three to four minutes). Used when the sport has a high need for the ATP-PC system (field events, football, powerlifting) or when heavy weights requiring skill are lifted.
• To stress the lactic acid system (for sports such as wrestling), rest periods are short (less than one minute) and are taken after each exercise or after a group of exercises, forcing the muscles to adapt to a shorter rest period.

• Strength goal: trained lifters gain the most strength with rests over 2 min; 60–120 s is enough for untrained people (Grgic 2018).
• Phosphocreatine recovery is biphasic: fast half-time 21–22 s, slow half-time over 170 s (Harris 1976).
• Muscular endurance: 30–60 s between sets.
• Hypertrophy: rest over 60 s gives a small advantage, with no further difference past about 90 s (Singer 2024); 3 min beat 1 min for strength and size in trained men (Schoenfeld 2016). Historically, bodybuilding routines used 60–90 s.
• Large muscles (quads/squats): 3–5 min between sets.
• Original COMBO program: 1½–2 min between sets.
• Strength emphasis: 3–4 min; mass emphasis in the original program: 1–2 min (longer is fine, see above).
• ATP-PC stress: ≥4 min (practically 3–4 min) after each exercise.
• Lactic acid stress: <1 min, after each exercise or circuit.