A complete guide to the best rep structure
When looking to add muscle in the gym, every rep counts. But it’s not just how many you perform per exercise that matters. How you execute each rep and combine multiple reps in varying structures can materially impact your gains.
Each repetition, or rep you perform of an exercise is the fundamental element of any weight lifting programme. Correctly executing reps initiates the adaptive response that increases strength and muscle size.
The rep defined
The rep is defined as a single cycle of lifting a weight in a controlled manner, using the correct form and technique for a specific exercise. Consecutively executing one or more reps completes a set.
A proper rep has numerous components, including composition, tempo, structure, form and function.
In terms of its composition, a rep consists of three distinct phases:
- The concentric phase
- The transition phase
- The eccentric phase
During the concentric phase, the muscle contracts (shortens) when lifting or pulling the weight. The transition phase is the mid-point of the rep and is generally considered the peak point of the lift. This is followed by the eccentric phase used to return the weight to the starting position. The eccentric phase also involves muscle contraction as the antagonist (opposing) muscles contract to return the agonist (exercise-initiating) muscle to its resting position in a controlled manner.
How you breath during each phase of a rep is also an important consideration. The recommended technique is to exhale on the concentric phase because you exert the greatest force during this phase, and inhale on the eccentric phase. Do not hold your breath during reps.
Find the right rep range
The number of reps you complete in a set is based the specific training response and adaptations you are after. Low reps elicit a different response to higher reps as this rep structures target different energy, neural and metabolic pathways.
For strength:
A low rep range of between 1-5 reps using heavy weights (typically 80-90% of your one-rep max, or 1RM) is used to increase strength and power. Working in this rep range generally triggers neurological adaptations by recruiting more muscle fibres to execute these short duration, intense and forceful reps, specifically the fast-twitch fibres that generate the most power. This improved neural recruitment translates to greater strength gains over time.
For growth:
The rep range that best targets muscle growth (hypertrophy) and structural adaptations is the 6-12 rep range. This rep range balances load and time under tension to deliver the ideal mechanical stress needed to stimulate the adaptations that support muscle growth by triggering muscle repair and growth at a cellular level.
For endurance:
Lifting beyond 12 reps per set starts stimulating metabolic and cellular adaptive responses, like improving lactate thresholds and glycolysis, which are the adaptations that support improvements in endurance.
Muscle-sparing benefits
BCAAs play important roles in limiting tissue damage during intense exercise, and help to repair and build muscle tissue. The muscle-sparing effect you get from BCAAs is an important attribute that makes these products ideal for use before and during training.
These supplements provide free-form amino acids, which offer a high bioavailability because the digestive system doesn’t have to break down complete proteins to get them. As such, BCAAs reach muscle cells quicker and get to work faster.
Timing is important
While weight training plans typically define how many reps to perform for each set to achieve a specific objective, they seldom indicate the correct tempo.
Lifting tempo refers to the time (in seconds) taken in each phase of the rep. Common lifting tempos popularised by strength trainers such as Australian Ian King and Canadian Charles Poliquin normally refer to three or four numbers.
An example is a 2:1:2 tempo denotes a concentric phases of two seconds, with a one second pause during the transition phase, followed by a two second eccentric phase.
When a fourth number appears, for example 1:2:1:2, it generally refers to the pause at the bottom of the movement (i.e. not the transition phase). An example of this would be the time spent with the bar in the air (starting position), above your chest, during a bench press.
Using a specific tempo helps you better target energy systems and muscular adaptations by increasing the time your muscle spends under tension, which can recruit more muscle fibres. The correct tempo can also improve form by limiting swinging and reducing the momentum used during a lift, which reduces injury risk.
What science says
Limited studies have probed the impact of tempo, but the available research offers some insights. In a 2005 study¹ that looked at the effect of the number of sets and contraction speed for strength development rep, the fast group used a tempo of 1010 while the slow group used a 3030 tempo. Based on the results, the researchers concluded: “Training fast produces greater strength increases than training slow”.
Interestingly, a meta-analysis² that looked at the effect of rep duration during resistance training on muscle hypertrophy found no difference in hypertrophy between rep durations. The research team, led by respected sports scientist Brad Schoenfeld, concluded that “a fairly wide range of repetition durations can be employed if the primary goal is to maximize muscle growth.”
While the findings suggest that training at “volitionally very slow durations (>10s per repetition) is inferior from a hypertrophy standpoint”, a lack of controlled studies on the topic makes it difficult to draw definitive conclusions.
Advanced rep options
The final consideration is the type of rep you perform, particularly if you are trying to increase your training volume. More advanced rep variations that you can include in your training plan include.
- Assisted reps: An assisted rep is executed after momentary muscular failure, where a spotter provides the lifter with the minimum amount of assistance required to get the weight past the moment of inertia or the ‘sticking point’ of the exercise. This allows the lifter to increase their training volume and time under tension, without sacrificing form and risking injury.
- Rest-pause reps: Having worked to failure in a set, the lifter will rack the weight and take a very short break before performing another repetition. You can repeat this process numerous times to maximise the effectiveness of this form of training, which includes improving metabolic pathways, such as the ATP half-life cycle and delivering improved muscle pumps (increase the flow of blood to the working muscle).
- Weight stripping: This is similar to rest-pause reps, but each subsequent rep uses less weight each time.
- Negative reps: Negative reps focus on the eccentric phase of the rep by increasing the time under tension during this phase. A spotter will normally assist the lifter on the concentric phase, to get the weight up and the lifter slowly lowers the weight.
- Partial reps: Partial reps are done when only a portion of the entire exercise movement is executed. The reason for doing this would be to elicit a greater muscular adaptive response by using heavier weights than you can lift when using a full range of motion and proper form.
References
- Munn J, Herbert RD, Hancock MJ, Gandevia SC. Resistance training for strength: effect of number of sets and contraction speed. Med Sci Sports Exerc. 2005 Sep;37(9):1622-6. doi: 10.1249/01.mss.0000177583.41245.f8. PMID: 16177617.
- Schoenfeld BJ, Ogborn DI, Krieger JW. Effect of repetition duration during resistance training on muscle hypertrophy: a systematic review and meta-analysis. Sports Med. 2015 Apr;45(4):577-85. doi: 10.1007/s40279-015-0304-0. PMID: 25601394.