Rest intervals between sets have been considered to be an important factor that can be used to fit the goal of a program. Rest intervals are dependent upon training intensity, goals, fitness level and targeted energy system. This is pretty much based off of the individual’s specific needs. The amount of rest between sets and exercises affects metabolic, hormonal, and cardiovascular responses to resistance exercise, performance, and training adaptions. The ability to attain consistent repetitions is dependent of the rest interval. The length of the rest interval must be sufficient enough to recover energy sources such as ATP and PCR systems, clear fatigue producing substances and restore force production(3). Studies suggest regardless of the muscle action 75 percent of muscular strength is recovered within the first minute with additional 2-3 minutes needed to recover for full strength. However muscle mass and the type of muscles used should be considered. For example movements like the squat or deadlift require all muscle actions and should require 3 to 5 minute rest intervals. However, when training small or large muscle groups in isolation 1 minute rest intervals might be sufficient.
Rest intervals are pretty simple in the fact that short resting intervals are used for muscular hypertrophy and endurance consisting of 30 seconds to 2 minute rest intervals, whereas long resting intervals are used for strength and power training, consisting of 3 to 5 minute rest intervals. When considering the rest interval between sets, slow-twitch muscle fibers would require shorter recovery due to their oxidative characteristics, whereas fast-twitch muscle fibers would require longer recovery due to their glycolytic characteristics.(1)The amount of rest between sets has a significant impact on training volume. Thus, the greater the rest interval the greater the volume performed. Short rest intervals of 1 minute or less have been shown to increase lactic acid levels during heavy strength training. In one study I found that 5 minutes was the time needed for lactic acid clearance but I believe that 3 minutes is enough time to clear lactic acid in trained individuals. I also found that when performing a one rep max over 90 percent that only a 1-2 minute rest is sufficient enough to recover and that 90 percent of phosphagens can be recovered within one minute following a high intensity set such as a max rep. However everything is dependent on the individual. Short and long resting intervals should be implemented to maximize hypertrophy and strength gains.
Hypertrophy and endurance training are a result from short resting intervals along with moderate to heavy weight and higher repetitions performed. The energy system mainly used with short rest intervals is the ATP-PC and glycolysis with minor contribution from aerobic metabolism. When training for hypertrophy or muscular endurance, rest periods are usually between 30 seconds to 2 minutes. Muscle strength may increase using short rest intervals but at a slower rate. Short rest intervals are shown to be a anabolic hormone stimulator, stimulator of local blood flow and to increase muscle protein synthesis and lactate production. Short rest intervals can be effective for strength increases in less trained muscles or exercises. Short rest intervals of 1 minute or less have been shown to increase lactic acid levels during heavy strength training. The rest interval length will vary by individual or goal of that particular exercise, but not every exercise will use the same rest interval.
Greater strength increases are a result from longer rest periods, heavy weight and fewer repetitions performed. The energy system mainly used with long rest intervals is the ATP-PC system. When training for absolute strength or power, rest periods consisting of 3-5 min are recommended for multi joint exercises. One study showed that the highest volume achieved each set was by the 5 minute rest interval. Studies show that the majority of phosphagen repletion occurs within 3 minutes. The importance of recovery is optimal during strength and power training because the performance of maximal lifts requires maximal energy. The rest interval length will vary by individual or goal of that particular exercise, but not every exercise will use the same rest interval.
Hypertrophy/Strength/Endurance Training (Short Rest Intervals)
Amount of load = moderate to heavy
Higher Reps = 6-12
Energy System = ATP-PC and glycolysis w/minor contribution from aerobic metabolism
Rest Interval = Short (30sec-2min)
Strength/Power Training (Long Rest Intervals)
Amount of load = Heavy
Lower Reps = 1-6
Energy System = ATP-PC
Rest Interval = Long (3-5 min)
My first reference was a group of 15 college men with experienced lifting. (3 strength training workouts, a week for at least 3 years. The data was collected over a 4 week period with testing 1 time a week. Subjects continued their normal workout routine throughout the study, but could not perform bench or squats in their personal workouts. They also did not exercise on the testing day. The test consisted of 4 sets of squats and bench with a 1, 2, or 5 minute rest interval between sets. Prior to the test the subjects completed two warm up sets. The first work set the subjects performed their 8RM. Subjects tested under 3 second eccentric followed by a 1 second concentric. The bench and squat were performed with an Olympic weight bar through a full ROM. There was a big difference in the 1 minute and 5 minute rest interval and between 2 and 5 minute rest intervals. There was no significant difference between 1 and 2 minute rest intervals. With the number of rest intervals being increased the volume increased.
My second reference took multiple studies focusing on muscular strength, type of muscle action, magnitude of load lifted, muscular power, muscular hypertrophy and muscular endurance. The first study was on muscular strength and power, which took 2 groups for 4 weeks and split them up into 40 sec and 160 sec intervals. They found that the 160 sec rest intervals led to greater strength and a higher volume of work compared to the 40 second group. Another study done on muscular strength was done with 3 groups with 30 second, 90 second and 3 minute individuals comparing squat strength. The subjects performed 5 set of 10 reps, 2 times a week for 5 weeks. The 3 minute group showed a greater strength increase. One study dealing with the magnitude of the load found that when training with less than 90% of the 1RM that 3 to 5 minute recovery was needed. They also found that when training over 90 % of 1RM individuals only needed 1 to 2 minute rest intervals. One study on muscular power took subjects with 1, 3, and 5 minute rest intervals and did 10 sets of 6 reps on the bench press using 70 % of their 1RM. They found that decreases in power came from the 1 minute rest interval and that the 3 minute rest interval was sufficient enough to maintain power. One study on muscle hypertrophy found that individual who did 3 set of 8 reps with 1 minute rest intervals showed greater increases of GH. One study on muscular endurance found that when training for max muscular endurance individuals should lower the intensity to achieve max results.
My third reference took a group 16 recreationally trained men who randomly got assigned to 1,3,5 minute rest interval groups. This was is to determine the effects of different rest intervals on upper and lower body strength after a 16 week resistance training program. Each group performed same nonlinear periodized training model. Max strength was taken at baseline, 8 weeks and the 16th week, for the leg press and bench press. The results for the bench press were increased by the 3 and 5 minute group, and both were significantly higher than the 1 minute group. However, for the leg press all groups were significantly stronger but both the 3 and 5 minute group were stronger than the 1 minute.
Willardson, Jeffery; A Brief Review: Factors Affecting The Length of The Rest Intervals Between Resistance Exercise Sets. Journal of Strength and Conditioning Research, 2006, National Strength and Conditioning Association
Willardson, Jeffery; Upper and Lower Body Strength Increases Consequent to Different Inter-Set Rest Intervals in Trained Men. Journal of Strength and Conditioning Research, 2010, National Strength and Conditioning Association
Burnkett, Lee; Willardson, Jeffery; A comparison of 3 Different Rest Intervals on The Exercise Volume Completed During a Workout. Journal of Strength and Conditioning Research, 2005, National Strength and Conditioning Association
Written by John Toston