Rest Intervals For Bodybuilding

Rest intervals between sets are an important factor that helps define your bodybuilding routine. They are defined by training intensity, goals, fitness level, and targeted energy system. This is based off of the individual’s specific needs. The amount of rest between sets affects several training aspects. These include metabolic, hormonal, cardiovascular, performance, and training adaptions. The ability to attain consistent repetitions is dependent on the rest interval. The rest period must be sufficient enough to recover energy sources such as ATP and PCR systems. Additionally, it helps clear fatigue producing substances and restore force production (3).

Studies suggest that 75% of your strength is recovered within one minute of rest. This is true regardless of the exercise. To recover your full strength, an additional 2-3 minutes is needed. However, muscle mass and the muscles being used should be considered. For example, movements like the squat or deadlift require all muscle actions. Exercises like this require 3 to 5 minutes rest. However, when using isolation exercises, one minute rest is sufficient.

Length Of Rest Intervals

Rest intervals are pretty simple. Short intervals are used for muscular hypertrophy and endurance. These range from 30 seconds to 2 minutes. Long intervals are used for strength and power training. These range from 3 to 5 minutes. Slow-twitch muscle fibers require shorter recovery time. This is due to their oxidative characteristics. Fast-twitch muscle fibers require longer recovery time. This is due to their glycolytic characteristics.(1)The amount of rest between sets has a significant impact on training volume. Therefore, the greater the rest interval the more training volume you can perform.

Shorter Rest Intervals

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. However, 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%, only a 1-2 minute rest is sufficient. Up to 90% of phosphagens can be recovered within one minute following a high intensity set. However everything is dependent on the individual. Short and long rest intervals should be implemented to maximize hypertrophy and strength gain

Hypertrophy & Endurance

Hypertrophy & endurance training is a result of short rest intervals, moderate to heavy weight, and higher reps. The energy systems used with short rest periods is the ATP-PC and glycolysis. In addition, there’s minor contribution from aerobic metabolism. When training for hypertrophy or muscular endurance, rest periods are usually between 30 seconds to 2 minutes. Furthermore, strength may increase using short rest periods but at a slower rate. Short rest intervals are shown to be a anabolic hormone stimulator. As well, they are a stimulator of local blood flow. Additionally, they increase muscle protein synthesis and lactate production.

Rest Intervals For Strength & Power

Using short rest intervals can be effective for strength increases in less trained muscles or exercises. In addition, rest periods of 1 minute or less increase lactic acid levels during heavy strength training. The length will vary by individual or goal of that particular exercise. Of course, not every exercise will require the same amount of rest between sets.

Longer rest periods, heavy weight and fewer repetitions leads to improved strength. The energy system mainly used with long rest periods 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 used a 5 minute rest interval. In addition, studies show that the majority of phosphagen repletion occurs within 3 minutes.

The importance of recovery is optimal during strength and power training. This is because the performance of maximal lifts requires maximal energy. The rest interval length will vary by individual or goal for that particular exercise. Length of rest between sets varies based on the exercise.

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)

Research Recap

My first reference was a group of 15 college men with lifting experienced. These individuals have been performing 3 strength training workouts a week for at least 3 years. The data was collected over a 4 week period with testing once a week. Subjects continued their normal workout routine throughout the study. However, they could not perform bench or squats in their personal workouts. They also did not exercise on test days. The test consisted of 2 warm up sets followed by 4 sets of squats and bench presses. Rest intervals were 1, 2, or 5 minutes between sets.

Test subjects performed their 8RM for the first work set. The test subjects used a 3 second eccentric followed by a 1 second concentric. They performed the bench press and squat using an Olympic weight bar. All exercises used a full ROM. There was a big difference in the 1 minute and 5 minute rest intervals. Also, there was a big difference between the 2 and 5 minute rest intervals. There was no significant difference between 1 and 2 minute rest intervals. Volume increased due to the increased number of rest intervals.

Additional Research Recap

My second reference looked at multiple studies. These studies focused on strength, type of muscle action, magnitude of load lifted, power, hypertrophy and muscular endurance. The first study was on muscular strength and power. This study took 2 groups for 4 weeks and split them up into 40 sec and 160 sec intervals. The 160 sec rest interval group had greater strength and performed a higher volume of work. This was compared to the 40 second group.

Another study done on strength was done with 3 groups. It used 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 found that 3-5 minute rest intervals were needed when training with less than 90% of 1RM.

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. These individuals did 10 sets of 6 reps on the bench press at 70% of their 1RM. They found that decreases in power came from the 1 minute rest interval. The 3 minute rest interval was sufficient enough to maintain power.

Another study on hypertrophy found that individuals doing 3 sets of 8 reps with 1 minute rest increased GH production. A study on endurance found that when training for max endurance, individuals should use lower intensity.

Rest Intervals – More Research

My third reference took a group 16 recreationally trained male test subjects. They were randomly 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. Also, this was after a 16 week resistance training program. Each group performed the same nonlinear periodization training model. Exercises used were the leg press and the bench press. Max strength was tested at baseline, 8 weeks and the 16th week. The results for the bench press were increased by the 3 and 5 minute group. Both were significantly higher than the 1 minute group. However, for the leg press all groups were significantly stronger. However, both the 3 and 5 minute group were stronger than the 1 minute.

References

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

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