How Effective Are Multiple Set, ‘Hypertrophic’ Protocols?
A Review of One Study
Ahtiainen JP, Pakarinen A, Alen M, Kraemer WJ, Hakkinen K. Short vs long rest period between the sets of hypertrophic resistance training: Influence on muscle strength, size, and hormonal adaptations in trained men. Journal of Strength and Conditioning Research. 2005; 19: 572-582.
The new American College of Sports Medicine (ACSM) Guidelines for Exercise Testing and Prescription1 recommend simple, low-volume, time-efficient resistance training protocols for all trainees, regardless of training experience. These new guidelines are in stark contrast to the complex, multi-set, high-volume, time-consuming periodization protocols formerly recommended in the ACSM’s 2002 position stand on resistance training2.
The National Strength and Conditioning Association (NSCA) continues to endorse complex, high-volume training protocols that are similar to the outdated ACSM Guidelines. Further, the NSCA claims that the stimulus required for experienced trainees is different (i.e., variable loading, inter-set rest time, and volume) from the stimulus required for novice trainees.
A critical analysis suggests that the outcomes are about the same3 regardless of the training protocol one uses.
The recent study by Dr. Ahtianen and his colleagues from Finland plus Dr. Kraemer from the U.S., a key NSCA figure, demonstrates that the typical NSCA based protocols may be ineffective and possibly harmful for some people.
The researchers manipulated the inter-set time interval and percent of 1 RM in a study involving 20 men, average age 28.7, and with a average of 6.6 years of resistance training experience. The aim of the study was to examine the effects of the different inter-set interval time on hormonal level, muscular hypertrophy, and strength.
With virtually no supporting evidence3, the outdated 2002 ACSM position stand2 claimed that specific inter-set time intervals and use of varying percentages of 1 RM differentially influenced hypertrophy and strength outcomes. Shorter inter-set time intervals, for example, allegedly produce a hormonal response more conducive to muscular hypertrophy.
Ahtianen and colleagues used the term ‘hypertrophic’ to describe these different protocols. This is not precise scientific nomenclature. There is neither an empirical definition for that term nor any data to support the idea that any given resistance training protocol can produce better muscular hypertrophy outcomes than any other protocol.
In this six-month study, two protocols were investigated and also used for assessing hormonal responses. One protocol involved five sets of leg presses and four sets of Smith machine squats all for 10 repetitions with two minutes between sets. The other protocol involved four sets of leg presses and three sets of squats with five minutes between sets. The load in this longer inter-set protocol was 15% greater than the protocol using the two-m inute interval. Loads were adjusted in each protocol so that 10 repetitions could be completed. When training with the higher load protocol, participants could receive assistance to complete the set.
Participants were randomly assigned to one of two groups: a group that began with the shorter inter-set training protocol and a group that started with the longer inter-set protocol. At the end of three months, participants in the training groups switched to the other protocol in a ‘cross-over design’.
Participants also carried out a full training program four days per week following the loading and inter-set time interval of their given protocol during a three-month period. Lower body training was performed once per week with the leg extension added to the leg press and squat. Other muscle groups were trained on the other three days per week following the respective loading, set, repetition, and inter-set time interval.
Ahtiainen et al. found that there was not a differential hormonal response to the protocols with different inter-set intervals. They also found very minimal strength gains and increases in muscle mass in the quadriceps.
At baseline, participants weighed a average of 83.9 kg with an average of 14.8% body fat, and at the end of six months they weighed an average of 84.6 kg with a average of 15.3% body fat. Despite involving male participants at an optimal point in life to enhance body composition, six months of training following NSCA recommended protocols resulted in no changes in body composition. The protocols were ineffective.
Of even greater importance was that seven participants of the 20 originally randomized, did not complete the study. The authors noted that the participants withdrew ‘…mostly due to training-induced aches in the knees and back’ (p. 573). This means that for the younger men in the study, there was greater than a one in three chance that following these NSCA protocols would result in injuries that halted their training.
Curiously, missing from the three and a half page, double column discussion section of the article was any mention of the main outcomes of this study - the ineffectiveness of the protocols and the injuries to 35% of the participants.
Bottom-line: This study suggests that the time between sets has no effect on strength or muscular hypertrophy outcomes. These findings support a recent critical analysis3 showing that the inter-set interval and other variables such as number of sets performed per exercise do not reliably affect strength and muscular hypertrophy.
The study also shows that protocols following NSCA recommendations may be minimally effective and could lead to injuries for at least a segment of people.
The study also illustrates another important point rarely noted by the ACSM or the NSCA. After training for a number of years, it is difficult for even younger men to appreciably increase strength or muscle mass. We do not know if a simple, lower volume, time-efficient protocol such as now recommended by the ACSM1 would have resulted in gains in strength and muscle mass for these already trained men. We do know that the currently recommended protocols1 would take much less time to perform than the NSCA protocols and there is no evidence to suggest they would result in injuries.
The Journal of Strength and Conditioning Research has displayed scientific integrity. The flagship journal of the NSCA allowed data and science to rule and showed that the resistance training protocols the organization has long advocated may be relatively ineffective and potentially injurious for some people.
References
ACSM. ACSM's Guidelines for Exercise Testing and Prescription (7th ed.). 2005; Baltimore, MD: Williams & Wilkins.
American College of Sports Medicine. Position Stand: Progression models in resistance training for healthy adults. Medicine and Science in Sports and Exercise. 2002; 34: 364-80.
Carpinelli RN, Otto RM, Winett RA. A critical analysis of the ACSM Position Stand on Resistance Training: Insufficient evidence to support recommended training protocols. Journal of Exercise Physiology Online. 2004; 7(3): 1-60.
A Review of One Study
Ahtiainen JP, Pakarinen A, Alen M, Kraemer WJ, Hakkinen K. Short vs long rest period between the sets of hypertrophic resistance training: Influence on muscle strength, size, and hormonal adaptations in trained men. Journal of Strength and Conditioning Research. 2005; 19: 572-582.
The new American College of Sports Medicine (ACSM) Guidelines for Exercise Testing and Prescription1 recommend simple, low-volume, time-efficient resistance training protocols for all trainees, regardless of training experience. These new guidelines are in stark contrast to the complex, multi-set, high-volume, time-consuming periodization protocols formerly recommended in the ACSM’s 2002 position stand on resistance training2.
The National Strength and Conditioning Association (NSCA) continues to endorse complex, high-volume training protocols that are similar to the outdated ACSM Guidelines. Further, the NSCA claims that the stimulus required for experienced trainees is different (i.e., variable loading, inter-set rest time, and volume) from the stimulus required for novice trainees.
A critical analysis suggests that the outcomes are about the same3 regardless of the training protocol one uses.
The recent study by Dr. Ahtianen and his colleagues from Finland plus Dr. Kraemer from the U.S., a key NSCA figure, demonstrates that the typical NSCA based protocols may be ineffective and possibly harmful for some people.
The researchers manipulated the inter-set time interval and percent of 1 RM in a study involving 20 men, average age 28.7, and with a average of 6.6 years of resistance training experience. The aim of the study was to examine the effects of the different inter-set interval time on hormonal level, muscular hypertrophy, and strength.
With virtually no supporting evidence3, the outdated 2002 ACSM position stand2 claimed that specific inter-set time intervals and use of varying percentages of 1 RM differentially influenced hypertrophy and strength outcomes. Shorter inter-set time intervals, for example, allegedly produce a hormonal response more conducive to muscular hypertrophy.
Ahtianen and colleagues used the term ‘hypertrophic’ to describe these different protocols. This is not precise scientific nomenclature. There is neither an empirical definition for that term nor any data to support the idea that any given resistance training protocol can produce better muscular hypertrophy outcomes than any other protocol.
In this six-month study, two protocols were investigated and also used for assessing hormonal responses. One protocol involved five sets of leg presses and four sets of Smith machine squats all for 10 repetitions with two minutes between sets. The other protocol involved four sets of leg presses and three sets of squats with five minutes between sets. The load in this longer inter-set protocol was 15% greater than the protocol using the two-m inute interval. Loads were adjusted in each protocol so that 10 repetitions could be completed. When training with the higher load protocol, participants could receive assistance to complete the set.
Participants were randomly assigned to one of two groups: a group that began with the shorter inter-set training protocol and a group that started with the longer inter-set protocol. At the end of three months, participants in the training groups switched to the other protocol in a ‘cross-over design’.
Participants also carried out a full training program four days per week following the loading and inter-set time interval of their given protocol during a three-month period. Lower body training was performed once per week with the leg extension added to the leg press and squat. Other muscle groups were trained on the other three days per week following the respective loading, set, repetition, and inter-set time interval.
Ahtiainen et al. found that there was not a differential hormonal response to the protocols with different inter-set intervals. They also found very minimal strength gains and increases in muscle mass in the quadriceps.
At baseline, participants weighed a average of 83.9 kg with an average of 14.8% body fat, and at the end of six months they weighed an average of 84.6 kg with a average of 15.3% body fat. Despite involving male participants at an optimal point in life to enhance body composition, six months of training following NSCA recommended protocols resulted in no changes in body composition. The protocols were ineffective.
Of even greater importance was that seven participants of the 20 originally randomized, did not complete the study. The authors noted that the participants withdrew ‘…mostly due to training-induced aches in the knees and back’ (p. 573). This means that for the younger men in the study, there was greater than a one in three chance that following these NSCA protocols would result in injuries that halted their training.
Curiously, missing from the three and a half page, double column discussion section of the article was any mention of the main outcomes of this study - the ineffectiveness of the protocols and the injuries to 35% of the participants.
Bottom-line: This study suggests that the time between sets has no effect on strength or muscular hypertrophy outcomes. These findings support a recent critical analysis3 showing that the inter-set interval and other variables such as number of sets performed per exercise do not reliably affect strength and muscular hypertrophy.
The study also shows that protocols following NSCA recommendations may be minimally effective and could lead to injuries for at least a segment of people.
The study also illustrates another important point rarely noted by the ACSM or the NSCA. After training for a number of years, it is difficult for even younger men to appreciably increase strength or muscle mass. We do not know if a simple, lower volume, time-efficient protocol such as now recommended by the ACSM1 would have resulted in gains in strength and muscle mass for these already trained men. We do know that the currently recommended protocols1 would take much less time to perform than the NSCA protocols and there is no evidence to suggest they would result in injuries.
The Journal of Strength and Conditioning Research has displayed scientific integrity. The flagship journal of the NSCA allowed data and science to rule and showed that the resistance training protocols the organization has long advocated may be relatively ineffective and potentially injurious for some people.
References
ACSM. ACSM's Guidelines for Exercise Testing and Prescription (7th ed.). 2005; Baltimore, MD: Williams & Wilkins.
American College of Sports Medicine. Position Stand: Progression models in resistance training for healthy adults. Medicine and Science in Sports and Exercise. 2002; 34: 364-80.
Carpinelli RN, Otto RM, Winett RA. A critical analysis of the ACSM Position Stand on Resistance Training: Insufficient evidence to support recommended training protocols. Journal of Exercise Physiology Online. 2004; 7(3): 1-60.