SCIENCE BEHIND INTRVL

REST PERIODS HAVE THE LARGEST IMPACT ON OUR WORKOUT DURATION. 

 

When distractions take over, your heart rate drops, and your muscles rest too long. Which not only lowers the intensity of your workout but also reduces calorie burn and overall progress.

As Technology has evolved and become more integrated into our daily lives, social distractions have made their way into our workouts, leading to wasted time with fewer results. Social media is filled with stories of gym-goers on their phones or socializing between sets. These distractions can significantly reduce the effectiveness of your workout and extend your gym time unnecessarily. 

When distractions take over, your heart rate drops, and your muscles rest too long. Which not only lowers the intensity of your workout but also reduces calorie burn and overall progress. 

The INTRVL band was created to help you maximize your workout efficiency, ensuring you achieve the best results in the shortest amount of time possible.

 

Understanding the science of rest periods can help you customize your workout to better align with your specific fitness goals

 

 

 

The science behind muscle recovery and recovery efficiency

The science of muscle recovery revolves around optimizing the balance between stress and rest to maximize muscle growth and performance. Resting between sets is crucial because it allows muscles to recover partially, replenishing energy stores (like ATP) and removing metabolic byproducts. 

Understanding the science of rest periods can help you customize your workout to better align with your specific fitness goals. Different types of exercises and objectives require varying rest times to optimize results. 

Research has indicated that rest interval between rests is an important variable that affects both acute responses and chronic adaptations to resist exercise programs. The 35 studies reviewed examined both acute responses and chronic adaptations, with rest interval length as the experimental variable.

 

 

 

 

 

 

Muscle Bilding: Moderate Intensity

• When the training goal is muscle hypertrophy, the combination of moderate-intensity sets with short rest intervals of 30-60 seconds might be the most effective due to greater levels of growth hormone during such workouts. 
  

High Intensity- low rep

• In terms of acute responses, a key finding was that when training with loads between 50% and 90% of one repetition maximum, 3-5 minutes' rest between sets allowed for greater repetition over multiple sets. Furthermore, in terms of chronic adaptations, resting 3-5 minutes between sets produced greater increases in absolute strength

 

Muscular Endurance

• Training with short rest intervals (e.g 20 seconds to 1 minute) resulted in higher repetition velocities during repeated sub-maximal muscle actions and also greater total torque during a high-intensity cycle test

 

Interval training:

•  Interval training involves exercise intensity close to VO2 MAX. It's typically used for aerobic endurance training with activities like running, biking, stair climbing, and swimming. Use work periods of 3-5 minutes and after that, rest.

 

 

 

 

 

ENERGY SYSTEMS:

The Phosphagen System

For strength activities such as a one-rep max (1RM) deadlift or bench press, the phosphagen system contributes most of the energy. It provides ATP (adenosine triphosphate), which is what your body uses to power muscular activity for a short-duration activities lasting up to 30 seconds.

If you're exercising very hard-say at 100 percent of your maximum oxygen uptake, or V02 MAX- you can burn through the entire glycogen stores of some muscles.

 

 

 

 

The Glycolytic System: If you work more then 30 seconds, up to 2 minutes, you're using the glycolytic energy system. It involves the breakdown of glycogen, which is stores glucose or glucose in the blood, to resynthesizes ATP. Bodybuilders typically train in a rep range and with an intensity that enlists the phosphagen and glycolytic stimulate growth, and refeed their muscles immediately.

The Oxidative System: At 2-3 minutes work, you'll still be using the glycolytic system, but will start to call on more of the oxidative, or aerobic system. The oxidative system uses carbohydrates, fats, and as a last resort, protein, for energy. Muscular endurance training can involve sets that last 2-3 minutes; for example, a set of 30 bodyweight squats or lunges may take 2 minutes to complete. Three sets of an exercise done for 20-30 reps will tap both the glycolysis and oxidative systems. During muscular endurance training, you'll rest 30 seconds or less between sets. 

Activities longer then 3 minutes, like going for a 1-mile run, primarily use the oxidative system. When performing such low-intensity training, you'll need to make sure that your electrolytes, hydration, and food intake are on point because it's a race against time before you get completely fatigued. During long, steady-state cardio workouts at low intensity, rest periods are typically taken as needed.

 

PRE-PROGRAMED TIMERS: We have pre-programmed the 1 and 3 minute timers to help get you started. Each coincides with proven scientific data to get results. It is important to note that resting times vary for each person depending on goals, experience, and exercise type. For that reason, all timers are customizable. 

 

3 minute

When building strength, there is less emphasis on muscle size and more emphasis on maximal power. Adequate rest between sets helps to maintain a high level of force production for the next set. According to the article, “Rest Interval Between Sets In Strength Training” from the National Library of Medicine, 35 studies were conducted to examine both acute responses and chronic adaptations, with rest interval length as the experimental variable. The study found that, “3-5 minutes' rest between sets allowed for greater repetitions over multiple sets. resting 3-5 minutes between sets produced greater increases in absolute strength, due to higher intensities and volumes of training.” Research shows this rest time to be optimal for strength development. 

1 minute

According to an article from healthline, “Rest between sets: what's right for me?” Studies have found that to induce muscle hypertrophy, optimal rest intervals are between 30–90 seconds. This duration allows for partial recovery of ATP and phosphocreatine levels, enabling lifters to maintain higher performance during their next set. Additionally, shorter rest intervals promote greater metabolic stress by keeping the muscles under tension, which can enhance muscle fiber recruitment and trigger hypertrophic responses. Overall, 1 minute rest periods can optimize training effectiveness, leading to greater muscle gains while preventing excessive fatigue.

How long you should rest between training sets will vary depending on whether you want to grow your muscle mass, lose weight, or improve your strength, power, or endurance. Our customizable timers give you the option to choose your own rest interval according to your personal goals.

 

Footnotes: 

1. National Library of Medicine; Sports Med;2009;39(9)

2. Bodybuilding.com, Mark Barroso, NSCA-CPT 9/24/2021