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Effect of rest interval length on the volume completed during upper body resistance exercise.

Introduction

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Resistance training can increase maximal strength, hypertrophy,

power, and localized muscular endurance. The prescriptive variables are

numerous, and may include: exercise order, rest intervals between sets

and exercises, frequency, velocity of movement, number of sets and

repetitions, and load or intensity. All of these variables can be

manipulated to meet specific training goals and address individual needs

(American College of Sports Medicine, 2002; Baechle and Earle, 2000;

Fleck and Kraemer, 2004; Weiss, 1991).

According to Fleck and Kraemer (2004), the length of the rest

interval between sets is an important variable when designing a

resistance exercise program. Although acknowledged, this variable is

rarely monitored precisely in field settings, despite its significant

impact on acute and chronic metabolic, hormonal, and cardiovascular

responses to resistance training (American College of Sports Medicine,

2002; Baechle and Earle, 2000; Fleck and Kraemer, 2004; Weiss, 1991).

Previous studies that examined rest interval lengths from 1 to 5

minutes between sets for single exercises demonstrated significant

differences in repetition performance and the exercise volume completed

(Kraemer, 1997; Larson and Potteiger, 1997; Ratamess et al., 2007;

Rahimi, 2005; Richmond and Godard, 2004; Willardson and Burkett, 2005;

Willardson and Burkett, 2006a; Willardson and Burkett, 2006b).

Ratamess et al. (2007) compared differences in workout volume

(resistance x repetitions per set) over five sets of the bench press

exercise when performed at two different intensities (i.e. 75% and 85%

of a 1-RM) and with five different rest intervals between sets (i.e. 30

seconds, 1, 2, 3, 5 minutes). The findings demonstrated that

irrespective of the intensity, workout volume (resistance x repetitions

per set) significantly decreased with each set in succession over five

sets when 30 seconds and 1 minute rest intervals were used. Workout

volume (resistance x repetitions per set) was maintained over two sets

for 2 minutes, three sets for 3 minutes, and fours sets for 5 minutes.

Consequently, the authors recommended that if more than 2 to 3 sets of

an exercise are performed, then at least 2 minutes of rest might be

needed to minimize loading reductions and maintain repetition

performance for the sets performed at the end of a workout.

However, a limitation of Ratamess et al. (2007) and similarly

designed studies (Kraemer, 1997; Larson and Potteiger, 1997; Rahimi,

2005; Ratamess et al., 2007; Richmond and Godard, 2004; Willardson and

Burkett, 2005; Willardson and Burkett, 2006a; Willardson and Burkett,

2006b) was the examination of single exercises, when typical resistance

sessions consist of multiple exercises for the same muscle groups

(American College of Sports Medicine, 2002; Baechle and Earle, 2000;

Fleck and Kraemer, 2004; Weiss, 1991). There is a great need for further

research to compare the volume completed over an entire resistance

exercise session with different rest intervals between sets. This would

contribute to general recommendations regarding resistance exercise

prescription to maximize volume; an important factor in developing

maximal strength (American College of Sports Medicine, 2002; Baechle and

Earle, 2000; Fleck and Kraemer, 2004; Weiss, 1991). Therefore, the

purpose of the current study was to compare the workout volume completed

during two upper body resistance exercise sessions that incorporated 1

minute versus 3 minute rest intervals between sets and exercises.

Methods

Experimental approach to the problem

In order to examine the effect of different rest intervals on the

workout volume completed (sets x resistance x repetitions per set), an

8-RM was assessed on three nonconsecutive days for the barbell bench

press (BBP), incline barbell bench press (IBBP), pec deck flye (PDF),

barbell lying triceps extension (BLTE), and triceps pushdown (TPD) with

the highest 8-RM load used to design the two exercises sessions. All

machine exercises (i.e. PDF, TPD) were performed on Life Fitness

equipment (Franklin Park, IL). Following the 8-RM assessments, subjects

completed two experimental resistance exercise sessions with either one

or three minutes rest between sets and exercises in a randomized

crossover design. The workout volume completed (sets x resistance x

repetitions per set) was recorded for each exercise during each session

and later compared between the rest interval conditions.

Subjects

Twelve men (23.58 [+ or -] 2.53 years; 1.74 [+ or -] 0.04 m; 74.33

[+ or -] 7.88 kg) with at least two years of recreational resistance

training experience, volunteered to participate in the current study.

All subjects answered “no” to all questions on the Physical

Activity Readiness Questionnaire–PAR-Q (Shephard, 1988) and signed an

informed consent form, in accordance with the Declaration of Helsinki.

Repetition maximum testing

The 8-RM assessments were conducted in the following order: BBP,

IBBP, PDF, BLTE, and TPD. In order to increase the reliability of the

8-RM assessments, the following strategies were employed: 1) all

subjects received standard instructions on exercise technique prior to

testing; 2) exercise technique was monitored and corrected as needed; 3)

all subjects received verbal encouragement during testing.

During the 8-RM assessments, each subject performed a maximum of

three 8-RM attempts for each exercise, with 5 minutes rest between

attempts (Miranda et al., 2007). After the 8-RM load for a specific

exercise was determined, a 10 minute rest interval was allowed prior to

the 8-RM assessment for the next exercise. No pause was allowed between

the eccentric and concentric phases of each repetition and a complete

range of motion (as normally defined) had to be completed. The 8-RM

testing demonstrated intraclass coefficients of BBP = 0.96, IBBP = 0.98,

PDF = 0.96, BLTE = 0.97, TPD = 0.98. A one-way ANOVA did not demonstrate

significant differences (p < 0.05) between the 8-RM loads for the

three assessment sessions.

Experimental resistance exercise sessions

In both experimental sessions, three sets of each exercise were

performed with 48 to 72 hours between sessions. Warm-up prior to each

session consisted of 2 sets of 12 repetitions of the first exercise

(BBP) at 40% of the 8-RM load. Subjects were verbally encouraged to

perform all sets to voluntary exhaustion. No attempt was made to control

the repetition velocity; however, subjects were required to utilize a

smooth and controlled motion with no pause between repetitions. The

workout volume completed (sets x resistance x repetitions per set) was

recorded for each exercise during each session and later compared

between the rest conditions.

Statistical analyses

The Shapiro-Wilk normality test and the homocedasticity test were

conducted prior to further statistical analysis (Bartlett criterion).

All variables presented normal distribution and homocedasticity. For

each exercise, a one-way ANOVA was conducted to compare the total

workout volume (sets x resistance x repetitions per set) completed for

the one minute versus three minute rest condition. A two (rest

conditions) by three (sets) by five (exercises) repeated ANOVA was also

conducted to compare differences in the repetitions per set between rest

conditions. An alpha level of p < 0.05 was used to determine the

significance of comparisons. The statistical analysis was conducted

using the software SPSS 17.0 for Windows (SPSS Inc., Chicago, IL).

Results

The total workout volume completed (sets x resistance x repetitions

per set) for all exercises was significantly greater for the three

minute rest condition versus the 1 minute rest condition (p < 0.05;

see Table 1). Within each rest condition, there were significant

differences in the repetitions completed for each exercise set (p <

0.05; see Table 2). Furthermore, there were significant differences

between rest conditions in the repetitions completed for most exercise

sets (p < 0.05; see Figure 1).

Discussion

The key finding from the current study was that a significantly

greater workout volume (sets x resistance x repetitions per set) was

completed for each exercise when resting 3 minutes between sets and

exercises (see Table 1). Because the resistance was constant for all

three sets of each exercise, these differences in workout volume could

be accounted for due to the greater repetitions completed per set for

the 3 minute rest condition (see Figure 1). The 3 minute rest condition

allowed for greater consistency in repetitions over all three sets,

whereas the 1 minute rest condition did not allow sufficient recovery

time. For example, there were no significant differences in the

repetitions completed between the first and second sets for any exercise

when resting 3 minutes between sets; however, there were significant

reductions between the first and second sets for three out of the five

exercises when resting 1 minute between sets (see Table 2).

These results were consistent with related studies that compared

repetition performance and the volume completed during the performance

of single exercises (Kraemer, 1997; Larson and Potteiger, 1997; Ratamess

et al., 2007; Rahimi, 2005; Richmond and Godard, 2004; Willardson and

Burkett, 2005; Willardson and Burkett, 2006a; Willardson and Burkett,

2006b). Willardson and Burkett (2005) compared repetition performance

when completing four sets of the back squat and bench press with an 8-

RM load and one, two, or five minute rest intervals. For the back squat,

the total repetitions progressively increased as the rest interval

increased: one minute (22.47 [+ or -] 4.79), two minutes (25.53 [+ or -]

4.29), and five minutes (28.80 [+ or -] 3.08). The same results were

demonstrated for the bench press: one minute (17.13 [+ or -] 4.42), two

minutes (21.60 [+ or -] 4.52), and five minutes (25.73 [+ or -] 4.23).

These results were consistent with the bench press results of the

current study in that the 3 minutes rest (21.3 [+ or -] 1.0) allowed for

significantly greater repetitions versus the 1 minute rest (18.6 [+ or

-] 0.5).

[FIGURE 1 OMITTED]

Another study by Willardson and Burkett (2006b) compared repetition

performance when completing five sets of the bench press with 50% and

80% of a 1-RM and one, two, or three minute rest intervals. Significant

increases in total repetitions were demonstrated as the rest interval

increased, irrespective of intensity. At 50% of 1-RM, the total

repetitions increased as follows: one minute (59.13 [+ or -] 10.31), two

minutes (74.81 [+ or -] 12.36), and three minutes (87.69 + 13.51). At

80% of 1-RM, the total repetitions increased as follows: one minute

(18.06 [+ or -] 4.64), two minutes (23.06 [+ or -] 5.95), and three

minutes (27.06 [+ or -] 5.37).

A limitation of these (Willardson and Burkett, 2005; Willardson and

Burkett, 2006b) and related studies (Kraemer, 1997; Larson and

Potteiger, 1997; Rahimi, 2005; Ratamess et al., 2007; Richmond and

Godard, 2004; Willardson and Burkett, 2005; Willardson and Burkett,

2006a; 2006b) was the evaluation of single exercises. One study to date

has compared different rest intervals in the context of a typical

resistance exercise session consisting of multiple exercises (Miranda et

al., 2007). Miranda et al. (2007) compared repetition performance during

upper body resistance exercise that emphasized the shoulder extensor

(e.g. latissimus dorsi, posterior fibers of the deltoid) and elbow

flexor (e.g. biceps brachii, brachialis, brachioradialis) muscle groups.

Six exercises were performed with 8-RM loads for three sets with either

one minute or three minutes rest between sets and exercises; similar to

the current study, significantly greater repetitions were completed for

all exercises when resting three minutes between sets (Miranda et al.,

2007).

The resistance exercises examined in the current study emphasized

the shoulder horizontal adductor (e.g. pectoralis major, anterior fibers

of the deltoid) and elbow extensor (e.g. triceps brachii) muscle groups.

Therefore, the findings of the current study when combined with the

findings of Miranda et al. (2007), suggest similar performance patterns

for antagonistic muscle groups of the upper body in recreationally

trained men.

The results of the current study are easily applied when

prescribing resistance exercises for the muscle groups examined.

Instituting three minutes rest between sets and exercises may result in

a significantly greater workout volume completed. However, it should be

noted that the findings of the current study are not applicable to a

sequence of lower body resistance exercises, which should be examined

alone or in combination with upper body resistance exercises in future

research.

Conclusion

The results of the current study add to the growing body of

knowledge regarding acute and chronic responses to different rest

intervals between resistance exercise sets. If sufficient time is

available, instituting longer rest intervals (e.g. three minutes) allows

for greater repetitions and workout volume versus shorter rest intervals

(e.g. one minute). This performance enhancement has been demonstrated

across a wide variety of exercises and muscle groups. Regarding the

series of resistance exercises examined in the current study, it is not

known whether resting more than three minutes between sets would further

increase the workout volume completed. There might be a point of

diminishing returns at which the rest interval between sets would become

excessive, and yield no further increases. Future research should

examine strength gains resulting from long-term training with shorter

versus longer rest intervals between sets. The results of this study may

have the greatest relevance to programs designed for maximal strength

for the maintenance of the load and repetitions per set.

Key points

* The length of the rest interval between sets is an important

variable when designing a resistance exercise program and may vary

depending on the characteristic being emphasized (i.e. maximal strength,

hypertrophy, localized muscular endurance, power).

* Although acknowledged, this variable is rarely monitored

precisely in field settings.

* Previous studies that examined rest interval lengths from 1 to 5

minutes between sets for single exercises demonstrated significant

differences in repetition performance and the exercise volume completed.

* There is a need for further research to compare the workout

volume (sets x resistance x repetitions per set) completed over an

entire resistance exercise session with different rest intervals between

sets.

* The results of the current study indicate that during a

resistance exercise session, if sufficient time is available, resting 3

minutes between sets and exercises allows greater workout volume for the

upper body exercises examined.

Received: 27 April 2009 / Accepted: 08 June 2009 / Published

(online): 01 September 2009

References

American College of Sports Medicine. (2002) Position stand:

Progression models in resistance training for healthy adults. Medicine

and Science in Sports and Exercise 34, 364-380.

Baechle, T.R. and Earle, T.W. (2000) Essentials of strength

training and conditioning. 2nd edition. Human Kinetics, Champaign.

Fleck, S.J. and Kraemer, W.J. (2004) Designing resistance training

programs. 3rd edition. Human Kinetics Champaign.

Kraemer, W.J. (1997) A series of studies: The physiological basis

for strength training in American football: Fact over philosophy.

Journal of Strength and Conditioning Research 11, 131-142.

Larson, G.D. and Potteiger, J.A.A. (1997) Comparison of three

different rest intervals between multiple squat bouts. Journal of

Strength and Conditioning Research 11, 115-118.

Miranda, H., Fleck, S.J., Simao, R., Barreto, A.C., Dantas, E.H.M.

and Novaes, J. (2007) Effect of two different rest period lengths on the

number of repetitions performed during resistance training. Journal of

Strength and Conditioning Research 21, 1032-1036.

Rahimi, R. (2005) Effect of different rest intervals on the

exercise volume completed during squat bouts. Journal of Sports Science

and Medicine 4, 361-366.

Ratamess, R.A., Falvo, M.J., Mangine, G.T., Hoffman, J.R.,

Faigenbaum, A.D. and Kang J. (2007) The effect of rest interval length

on metabolic responses to the bench press exercise. European Journal

Apply Physiology 100, 1-17.

Richmond, S.R. and Godard, P.M. (2004) The effects of varied rest

periods between sets to failure using the bench press in recreationally

trained men. Journal of Strength and Conditioning Research 18, 846-849.

Shephard, R.J. (1988) PAR-Q: Canadian home fitness test and

exercise screening alternatives. Sports Medicine 5, 185-195.

Weiss, L.W. (1991) The obtuse nature of muscular strength: The

contribution of rest to its development and expression. Journal of

Applied Sports Science Research 5, 219-227.

Willardson, J.M. and Burkett, L.M. (2005) A comparison of 3

different rest intervals on the exercise volume completed during a

workout. Journal of Strength and Conditioning Research 19, 23-26.

Willardson, J.M. and Burkett, L.N. (2006a) The effect of rest

interval length on the sustainability of squat and bench press

repetitions. Journal of Strength and Conditioning Research 20, 396-399.

Willardson, J.M. and Burkett, L.N. (2006b) The effect of rest

interval length on bench press performance with heavy versus light

loads. Journal of Strength and Conditioning Research 20, 400-403.

Humberto Miranda (1), Roberto Simao (2), Leonardo Marmo Moreira

(1), Renato Aparecido de Souza (1), Joao Antonio Alves de Souza (2),

Belmiro Freitas de Salles (3) and Jeffrey M. Willardson (4) ([mail])

(1) Institute of Research and Development, Vale do Paraiba

University, Sao Jose dos Campos, SP, Brazil, (2) Universidade Federal do

Rio de Janeiro, School of Physical Education and Sports, Rio de Janeiro,

RJ, Brazil, (3) Laboratory for Research in Microcirculation, Department

of Physiological Sciences, State University of Rio de Janeiro, Rio de

Janeiro, RJ, Brazil, (4) Department of Kinesiology and Sports Studies,

Eastern Illinois University, Charleston, IL, USA

([mail]) Jeffrey M. Willardson Eastern Illinois University,

Kinesiology and Sports Studies Department, 2506 Lantz Bldg, 600 Lincoln

Ave, Charleston, IL 61920, USA

AUTHORS BIOGRAPHY

Humberto MIRANDA

Employment

Universidade do Vale do Paraiba. Institute of Research and

Development. Sao Paulo.

Degree

MSc, PhD Student

Research interests

Resistance training and Skeletal Muscle investigations

E-mail: humbertomiranda01@gmail.com

Roberto SIMAO

Employment

Professor of School of Physical Education and Sports (EEFD/UFRJ).

Degree

PhD

Research interests

Resistance training and physiopathology and resistance training

variables (e. g. rest interval, exercise order).

E-mail: robertosimao@ufrj.br

Renato Aparecido de SOUZA

Employment

Assistant Professor

Universidade Federal dos Vales do Jequitinhonha e Mucuri (UFVJM)

Departamento de Fisioterapia Diamantina/MG, Brasil

Degree

PT, MSc, PhD student

Research interests

Skeletal Muscle investigations

E-mail: tatosouza2004@yahoo.com.br

Belmiro F. DE SALLES

Employment

Universidade do Estado do Rio de Janeiro. School of Physical

Education and Sports. Rio de Janeiro.

Degree

BSc, PhD Student

Research interests

Resistance training and physiopathology and resistance training

variables.

E-mail: belmirosalles500@hotmail.com

Leonardo Marmo MOREIRA

Employment

Institute of Research and Development of the Universidade do Vale

do Paraiba, Sao Paulo, Brazil.

Degree

PhD

Research interests

Biophysics and bioinorganic chemistry.

E-mail: leonardomarmo@gmail.com

Joao A.A.A. de SOUZA

Employment

Universidade do Estado do Rio de Janeiro. School of Physical

Education and Sports. Rio de Janeiro.

Degree

BSc

Research interests

Resistance training variables (e. g. rest interval, exercise

order).

E-mail: joaoedf@hotmail.com

Jeffrey M. WILLARDSON

Employment

Kinesiology and Sports Studies Department. Eastern Illinois

University. Charleston, IL, USA.

Degree

PhD

Research interests

Spinal stability, muscle fatigue, ergogenic aids.

E-mail: jmwillardson@eiu.edu

Table 1. Total workout volume (sets x resistance x repetitions

per set) for 1 min. versus 3 min. conditions. Data are means

([+ or -] SD).

Session BBP (kg) IBBP (kg) PDF (kg)

1 min. 1334 (405) 691 (241) 506 (202)

3 min. 1527 (468) * 1118 (329) * 776 (252) *

Session BLTE (kg) TPD (kg)

1 min. 460 (190) 394 (145)

3 min. 619 (227) * 655 (246) *

BBP = barbell bench press; IBBP = incline barbell bench press;

PDF = pec deck flye; BLTE = barbell lying triceps extension;

TPD = triceps pushdown. * Significant difference total workout

volume 1 min. versus 3 min. condition (p < 0.05).

Table 2. Comparison repetitions per set (mean [+ or -] SD) within

1 min. and 3 min. conditions. Data are means ([+ or -] SD).

Exercise/

Sequence Set 1 Set 2 Set 3

BBP

1 min. 8.40 (.22) * 6.42 (.51) 4.17 (.58)

([dagger]) ([double dagger])

3 min. 8.30 (.16) 7.33 (.49) 5.92 (1.01)

([dagger])

IBBP

1 min. 5.00 (.74) 3.92 (.67) 3.33 (.49)

([dagger])

3 min. 7.25 (.45) 6.58 (.51) 6.08 (.67)

([dagger])

PDF

1 min. 4.58 (.79) 3.83 (.72) 3.33 (.78)

3 min. 6.83 (.39) 5.92 (.67) 5.33 (.78)

BLTE

1 min. 6.50 (.91) * 4.92 (.90) 3.42 (1.01)

([dagger])

3 min. 7.33 (.65) 6.58 (.67) 6.01 (.74)

([dagger])

TPD

1 min. 4.75 (.62) * 3.08 (.79) 2.00 (.73)

([dagger]) ([double dagger])

3 min. 6.08 (.67) 5.33 (.65) 4.92 (.57)

([dagger])

BBP = barbell bench press; IBBP = incline barbell bench press;

PDF = pec deck flye; BLTE = barbell lying triceps extension;

TPD = triceps pushdown. * Significant difference repetitions

first set versus second set; ([dagger]) Significant difference

repetitions first set versus third set; ([double dagger]) Significant

difference repetitions second set versus third set (p < 0.05).

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