Single vs. Multi-Joint Resistance Exercises: Effects on Muscle Strength and Hypertrophy

Article (PDF Available)inAsian Journal of Sports Medicine 6(1) · March 2015with 12,188 Reads 
How we measure 'reads'
A 'read' is counted each time someone views a publication summary (such as the title, abstract, and list of authors), clicks on a figure, or views or downloads the full-text. Learn more
DOI: 10.5812/asjsm.24057
Cite this publication
Abstract
Background: Some authors suggest that single joint (SJ) exercises promote greater muscle hypertrophy because they are easier to be learned and therefore have less reliance on neural factors. On the other hand, some authors recommend an emphasis on multi-joint (MJ) exercises for maximizing muscle strength, assuming that MJ exercises are more effective than SJ execises because they enable a greater magnitude of weight to be lifted. Objectives: The present study aimed to compare the effects of MJ vs. SJ exercises on muscle size and strength gains in untrained young men. Patients and Methods: Twenty-nine young men, without prior resistance training experience, were randomly divided into two groups. One group performed (n = 14) only MJ exercises involving the elbow flexors (lat. pull downs), while the other (n = 15) trained the elbow flexors muscles using only SJ exercises (biceps curls). Both groups trained twice a week for a period of ten weeks. The volunteers were evaluated for peak torque of elbow flexors (PT) in an isokinetic dynamometer and for muscle thickness (MT) by ultrasonography. Results: There were significant increases in MT of 6.10% and 5.83% for MJ and SJ, respectively; and there were also significant increases in PT for MJ (10.40%) and SJ (11.87%). However, the results showed no difference between groups pre or post training for MT or PT. Conclusions: In conclusion, the results of the present study suggest that MJ and SJ exercises are equally effective for promoting increases in upper body muscle strength and size in untrained men. Therefore, the selection between SJ and MJ exercises should be based on individual and practical aspects, such as, equipment availability, movement specificity, individual preferences and time commitment.
Advertisement
Asian J Sports Med. 2015 March; 6(1): e24057. DOI: 10.5812/asjsm.24057
Published online 2015 March 22. Research Article
Single vs. Multi-Joint Resistance Exercises: Effects on Muscle Strength and
Hypertrophy
Paulo Gentil 1,*; Saulo Soares 1; Martim Bottaro 1
1Department of Physical Education, University of Brasilia, Brasilia, Brazil
*Corresponding author: Paulo Gentil, Department of Physical Education, University of Brasilia, Brasilia, Brazil, Tel: +55-613202-4731, E-mail: paulogentil@hotmail.com
Received: October 4, 2014; Accepted: October 4, 2014
Background: Some authors suggest that single joint (SJ) exercises promote greater muscle hypertrophy because they are easier to be
learned and therefore have less reliance on neural factors. On the other hand, some authors recommend an emphasis on multi-joint (MJ)
exercises for maximizing muscle strength, assuming that MJ exercises are more effective than SJ exercises because they enable a greater
magnitude of weight to be lifted.
Objectives: The present study aimed to compare the effects of MJ vs. SJ exercises on muscle size and strength gains in untrained young
men.
Patients and Methods: Twenty-nine young men, without prior resistance training experience, were randomly divided into two groups.
One group performed (n = 14) only MJ exercises involving the elbow flexors (lat. pull downs), while the other (n = 15) trained the elbow
flexors muscles using only SJ exercises (biceps curls). Both groups trained twice a week for a period of ten weeks. The volunteers were
evaluated for peak torque of elbow flexors (PT) in an isokinetic dynamometer and for muscle thickness (MT) by ultrasonography.
Results: There were significant increases in MT of 6.10% and 5.83% for MJ and SJ, respectively; and there were also significant increases in PT
for MJ (10.40%) and SJ (11.87%). However, the results showed no difference between groups pre or post training for MT or PT.
Conclusions: In conclusion, the results of the present study suggest that MJ and SJ exercises are equally effective for promoting increases
in upper body muscle strength and size in untrained men. Therefore, the selection between SJ and MJ exercises should be based on
individual and practical aspects, such as, equipment availability, movement specificity, individual preferences and time commitment.
Keywords:Resistance Training; Ultrasonography; Muscles; Hypertrophy
Copyright © 2015, Sports Medicine Research Center. This is an open-access article distributed under the terms of the Creative Commons Attribution-NonCommer-
cial 4.0 International License (http://creativecommons.org/licenses/by-nc/4.0/) which permits copy and redistribute the material just in noncommercial usages,
provided the original work is properly cited.
1. Background
Resistance training (RT) has been recommended by
many authors and scientists as an important compo-
nent of physical activity programs, specifically because
of its capacity to promote increases in muscle size and
strength (1-3). However, in order to ensure optimal re-
sults, the design of RT programs should be based on sci-
entific principles that consider the manipulation and
combination of several variables, such as rest interval,
movement velocity, training load, number of sets and ex-
ercise selection (3, 4). Although exercise selection is one
of the most questioned variables, it has received surpris-
ingly little attention by the scientific community.
In general, it is common to classify resistance exercises
as multi-joint (MJ) or single-joint (SJ), depending on how
many joints are involved in the movement. Some authors
suggest that SJ exercises promote greater muscle hyper-
trophy because they are easier to be learned and there-
fore have less reliance on neural factors than MJ exer-
cises (5, 6). On the other hand, some authors recommend
an emphasis on MJ exercises for maximizing muscle
strength, assuming that MJ exercises are more effective
than SJ exercises because they enable a greater magni-
tude of weight to be lifted (1, 3). However, evidences for
these claims are limited because of the lack of studies
comparing muscle hypertrophy and strength gains be-
tween SJ and MJ exercises, which make it difficult to cor-
rectly choose an exercise when designing a RT program.
A study of Giannakopoulos et al. (7) compared the ef-
fects of SJ and MJ exercises on shoulder cuff muscular
performance and reported greater increases in internal
and external rotation peak torque for the MJ group. How-
ever, the SJ group performed a lower number of sets and
at a lower intensity, which may limit the comparisons.
A previous study investigated the effects of adding SJ
exercises to a MJ protocol on muscle size and strength
of young men and reported no differences in changes
of elbow flexors’ muscle strength and size between the
groups that performed only MJ and the group that per-
formed MJ + SJ (8). However, since there was not a group
performing only SJ exercises, the study may be valuable
for analyzing training volume rather than exercise selec-
tion and the question remains whether an RT program
with only SJ exercise would be as efficient as a program
involving only MJ exercises.
Gentil P et al.
Asian J Sports Med. 2015;6(1):e240572
2. Objectives
Due to the importance of adequate exercise selection
for the design of effective RT programs and the lack of
studies comparing the chronic effects of SJ and MJ exer-
cises, the purpose of the present study was to compare
the effects of MJ and SJ exercises on the gains of muscle
size and strength of the elbow flexors in untrained young
men. Our hypothesis is that there is no difference in mus-
cle adaptations between the groups that perform MJ and
SJ exercises.
3. Patients and Methods
3.1. Experimental Procedures
Twenty-nine college aged young men, without prior
resistance training experience, were randomly divided
into two groups. One group performed only MJ exercises
(lat. pull downs) involving the elbow flexors, while the
other group trained the elbow flexor muscles using only
SJ exercises (arm curls). Both groups trained twice a week
with at least 48 hours between training sessions, for a
period of ten weeks. All exercises were carried out with
three sets of eight to 12 maximum repetitions (3). The vol-
unteers were evaluated for peak torque of elbow flexors
(PT) in an isokinetic dynamometer and for muscle thick-
ness (MT) by ultrasonography.
3.2. Participants
Thirty-four young men volunteered for the study. The
volunteers were recruited through folders and advertis-
ing banners around the university campus. To be accept-
ed, participants should be at least 18 years of age, have not
been participating in any resistance training program
over the past six months and be free of health problems
that could be aggravated by the experimental proce-
dures. To be included in the analysis, the participants
had to attend at least 80% of the training sessions (9).
The volunteers were instructed to not change their nu-
tritional habits and, if any relevant change was detected
(e.g. becoming a vegetarian, being on caloric restriction,
use of nutritional supplements or ergogenic substances,
etc.) the data of the participants were excluded from the
analysis. Data of five volunteers were excluded for failing
to meet the inclusion criteria, the exclusions occurred
due to low attendance (2), low adhesion to training pro-
tocol (2) and changes in nutritional habits (1). The charac-
teristics of the excluded participants did not differ from
the others. All volunteers were notified about the experi-
mental procedures, benefits and risks before signing the
informed consent form. An Institutional Research Ethics
Committee granted approval for the study.
3.3. Muscle Thickness
In the present study MT was assessed by an ultrasound
equipment. Ultrasound is a quick, reliable and cost-effec-
tive method to measure muscle size (10, 11). Participants
were tested before and after the 10-week training period
for MT of the elbow flexors of the right arm. All tests were
conducted at the same time of the day, and participants
were instructed to hydrate normally 24 hours before the
tests. Measures were taken 3 - 5 days after the last train-
ing session to prevent any swelling from contributing to
the MT measurement (12). During this time, participants
were oriented not to participate in any other exercise ses-
sions or intense activity involving the upper body. MT was
measured at 10 cm from the cubital fossa using B-Mode
ultrasound (Philips-VMI, Ultra Vision Flip, model BF). A
water soluble transmission gel was applied to the mea-
surement site and a 7.5 MHz ultrasound probe was placed
perpendicular to the tissue interface while not depress-
ing the skin. Once the technician was satisfied with the
quality of the image produced, the image on the monitor
was frozen. With the image frozen, a cursor was enabled
in order to measure MT, which was taken as the distance
from the subcutaneous adipose tissue-muscle interface
to muscle-bone interface (13). A trained technician per-
formed all analyses (14). The coefficients of variation for
elbow flexor MTs were less than 3.0%. Baseline test and
retest intraclass correlation coefficient (ICC) for elbow
flexors MT was 0.95.
3.4. Peak Torque
The concentric PT of the dominant arm’s elbow flexors
was tested on an isokinetic dynamometer Biodex System
3 (Biodex Medical, Inc., Shirley, NY) with two sets of four
repetitions at 60° s-1, and 60 seconds rest interval be-
tween sets. According to Feiereisen et al. (15), isokinetic
measurements should be preferentially used to evaluate
strength gains and limit bias between measurements
at different times. Calibration of the dynamometer was
performed before each testing session according to the
manufacturer’s specifications. Participants were seated
with their elbow on a Scott bench and aligned with the
axis of rotation of the dynamometer’s lever arm. The fore-
arm remained in a supinated position throughout the
test. Verbal encouragement was given throughout the
test, and all tests were administered by the same inves-
tigator. Baseline test and retest ICC and standard error of
the mean values for PT were 0.96 and 2.4%, respectively.
3.5. Resistance Training Protocol
Participants were randomly assigned to two groups.
The MJ group performed leg press, knee flexion; bench
press and lat. pull down. The SJ group also performed
leg press, knee flexion and bench press but, instead of
lat. pull down, they performed standing barbell biceps
curls. The lat. pull down was performed with a pronated
wide grip as defined previously by Lusk et al. (16) and no
specific instructions were given on how to emphasize
the latissimus dorsi or the biceps brachii. The standing
Gentil P et al.
3
Asian J Sports Med. 2015;6(1):e24057
barbell biceps curls was performed at a shoulder-width
supinated grip.
Training protocols followed the recommendations of
the American College of Sports and Medicine (3). All exer-
cises were performed with three sets of 8 - 12 maximum
repetitions (RM). Subjects were instructed to perform
the concentric and eccentric phases each in two seconds,
without pause between them. During the training ses-
sions, music tracks with 120 bpm were played in order to
facilitate control of movement speed. Participants were
oriented to perform all sets until concentric failure. If
necessary, loads were adjusted from set to set to main-
tain the designated number of repetitions. Training ses-
sions were closely supervised by experienced trainers,
because previous research has demonstrated greater
gains in supervised vs. unsupervised training (17). Train-
ing was conducted two days a week, with a minimum of
48 hours between sessions. Rest interval between sets
ranged from 1.5 to 2.5 minutes. Each participant filled
a training log for each workout, containing the loads
used, the number of repetitions performed in each set
and any relevant information (illness, pain, sleep depri-
vation), and all training logs were verified by a supervi-
sor following each exercise session.
3.6. Statistical Analysis
All values were reported as means and standard devia-
tions. Two way ANOVA 2 x 2 (group by time) with a be-
tween-within design was used to compare means. When
necessary, multiple comparisons with confidence inter-
vals adjusted by the Bonferroni procedure were used for
post hoc analysis. The significance level was established
as P ≤ 0.05. The statistical program SPSS version 16.0 was
used for statistical analysis.
4. Results
The characteristics of participants are presented in
Table 1. Table 2 presents the values of MT and PT pre and
post training. The ANOVA found no statistically signifi-
cant difference (P > 0.05) between groups pre or post
training for MT or PT. However, with respect to time (pre
vs. post), there were significant increases in MT of 6.10%
and 5.83% for MJ and SJ, respectively (P ≤ 0.05). PT also
significantly increases for MJ (10.40%, P ≤ 0.05) and SJ
(11.87%, P ≤ 0.05).
Table 1. Characteristics of the Subjects a
Variable Multi Joint
Group (n = 14)
Single Joint
Group (n = 15)
Age, y 23.4 ± 2.6 22.4 ± 2.1
Body weight, kg 73.1 ± 13.6 69.3 ± 5.8
Height, cm 171.9 ± 8.2 175.8 ± 5.9
a Data are presented as Mean ± SD.
Table 2. Muscle Thickness and Peak Torque Before and After 10
Weeks of Training a
Variable Multi Joint
Group
Single Joint
Group
Muscle thickness,
mm
Pre-training 31.80 ± 3.76 28.79 ± 2.76
Post-training 33.74 ± 3.40 b30.47 ± 4.67 b
Delta 6.10 5.83%
Peak Torque, N m
Pre-training 49.26 ± 9.49 49.69 ± 10.50
Post-training 54.38 ± 10.08 b55.59 ± 10.61 b
Delta 10.40 11.87
a Data are presented as Mean ± SD or %.
b P < 0.05, post vs. Pre.
5. Discussion
The major find of the present study was that there is
no significant difference on elbow flexor strength gains
and hypertrophy between MJ and SJ exercise. Exercise
selection is a crucial step when designing RT programs.
However, there are many controversies when choosing
an exercise, especially when deciding between SJ or MJ
exercises. Some authors suggest that SJ exercises would
promote greater increases in muscle size, because they
would have less reliance on neural factors (5, 6). On the
other hand, some authors (1, 3) suggest that MJ exercises
are more effective because they enable a greater mag-
nitude of weight to be lifted. This leads some people to
prefer SJ exercises while others give preference to MJ exer-
cises. However, the controversy remains because studies
comparing the chronic effects of MJ and SJ exercises on
strength gains and muscle hypertrophy are scarce.
In a previous study, Chilibeck et al. (6) reported that
the lean mass in the upper-body of women performing
RT increases more than in the lower-body. The authors
suggested that the more prolonged neural adaptation re-
lated to the more complex leg press exercise may have de-
layed muscle hypertrophy in the legs, while the arm curl
exercise promoted higher muscle hypertrophy due to
faster neural adaptation. However, the training program
also contained SJ exercises for the legs (knee extension
and knee flexion), as well as, MJ exercises that involved
the arms (bench press and lat. pull downs). Therefore, it
is not possible to make a direct comparison between SJ
and MJ exercises.
Recently, Gentil et al. (8) examined the effect of add-
ing SJ exercises to a MJ exercise program on upper body
muscle size and strength of young men. In the study, one
group performed only upper body MJ exercises (lat. pull
down and bench press) while the other performed the
same MJ exercises plus SJ exercises (elbow flexion and el-
bow extension). According to the results, there were no
differences in muscle size and strength gains between
Gentil P et al.
Asian J Sports Med. 2015;6(1):e240574
groups. However, since there was not a group that per-
formed only SJ exercises, the question remains whether
an RT program with only SJ exercise would be as efficient
as a program involving only MJ exercises.
We did not find studies comparing muscle hypertro-
phy responses between SJ and MJ exercises. One of the
few studies to compare the chronic effects of MJ and SJ
exercises on muscle performance was the study of Gi-
annakopoulos et al. (7) that analyzed the effects of two
training modes on shoulder cuff muscular performance.
The participants of the study were divided into 3 groups:
one group performed SJ exercises (internal and external
shoulder rotation using 2 kg dumbbells); one trained
with MJ exercises (lat. pull down, overhead press, reverse
pull up and push-up exercises); and the other had no
training. According to the results, the group that trained
with MJ exercises achieved greater increases in internal
and external rotation peak torque than the groups that
trained with SJ exercises.
Comparison between our study and the study of Gi-
annakopoulos et al. (7) are limited due to methodologi-
cal differences, and the difference between the results is
probably due to the differences in training volume and
intensity between protocols. In the study of Giannako-
poulos et al. (7) the SJ group performed a lower number of
sets compared to the MJ group. Additionally, the SJ group
trained at a constant load, with no load progression,
which may have limited the results. In the present study
the SJ and MJ groups performed an equal number of sets
of progressive resistance training and both trained with
maximal repetitions.
The results of the present study on muscle hypertro-
phy are unique and important for practical purposes.
Increase or maintaining muscle mass is an important
goal for health, fitness and performance. It has been
shown that muscle hypertrophy is dependent on the me-
chanical tension, muscle damage and metabolic stress
produced by the strength exercise (18, 19). Thus, accord-
ing to the results of the present study we may presume
that muscle strain and muscle damage caused by the MJ
and SJ exercise for the EF muscles was somewhat similar.
However, one of the limitations of the present study was
that the mechanisms involved in muscle hypertrophy
between MJ and SJ exercise were not evaluated. Further-
more, the finding that MJ exercises are as efficient as SJ in
muscle hypertrophy and strength may be valuable when
designing an RT program. In order to save time, strength
and conditioning, specialists can choose exercises that
target a higher number of muscle groups at a time. This
strategy can increase training volume and reduce the
time commitment, which, in turn, may improve exercise
adherence since lack of time is the most cited barrier for
an individual engaging in any exercise program (20-23).
The results of the present study shows that MJ and SJ
exercises are equally effective for promoting increases
in muscle strength and size in untrained men, confirm-
ing our hypothesis. It is well established that muscles in-
terpret environmental stimuli through mechanical and
metabolic changes (18, 19, 24-26) and it seems that these
responses will not differ if the movement is performed
alone (biceps curl, which involves only elbow flexion) or
accompanied by the movement of another joints (lat.
pull down, which involves elbow flexion and shoulder ex-
tension). Based on the present results, it can be suggested
that the selection between SJ and MJ exercises should be
based on individual and practical aspects, such as equip-
ment availability, individual preferences, movement
specificity, time commitment etc. Further studies are
required to test if the results will be the same in trained
people and other muscle groups.
References
1. Kraemer WJ, Adams K, Cafarelli E, Dudley GA, Dooly C, Feigen-
baum MS, et al. American College of Sports Medicine position
stand. Progression models in resistance training for healthy
adults. Med Sci Sports Exerc. 2002;34(2):364–80.
2. Kraemer WJ, Ratamess NA. Fundamentals of resistance train-
ing: progression and exercise prescription. Med Sci Sports Exerc.
2004;36(4):674–88.
3. American College of Sports M. American College of Sports Medi-
cine position stand. Progression models in resistance training
for healthy adults. Med Sci Sports Exerc. 2009;41(3):687–708.
4. Tan B. Manipulating Resistance Training Program Variables
to Optimize Maximum Strength in Men. J Strength Cond Res.
1999;13(3):289–304.
5. Rutherford OM, Jones DA. The role of learning and coordi-
nation in strength training. Eur J Appl Physiol Occup Physiol.
1986;55(1):100–5.
6. Chilibeck PD, Calder AW, Sale DG, Webber CE. A comparison of
strength and muscle mass increases during resistance train-
ing in young women. Eur J Appl Physiol Occup Physiol. 1998;77(1-
2):170–5.
7. Giannakopoulos K, Beneka A, Malliou P, Godolias G. Isolated
vs. complex exercise in strengthening the rotator cuff muscle
group. J Strength Cond Res. 2004;18(1):144–8.
8. Gentil P, Soares SR, Pereira MC, Cunha RR, Martorelli SS, Mar-
torelli AS, et al. Effect of adding single-joint exercises to a multi-
joint exercise resistance-training program on strength and
hypertrophy in untrained subjects. Appl Physiol Nutr Metab.
2013;38(3):341–4.
9. Gentil P, Bottaro M. Effects of training attendance on muscle
strength of young men after 11 weeks of resistance training.
Asian J Sports Med. 2013;4(2):101–6.
10. Bemben MG. Use of diagnostic ultrasound for assessing muscle
size. J Strength Cond Res. 2002;16(1):103–8.
11. Reeves ND, Maganaris CN, Narici MV. Ultrasonographic as-
sessment of human skeletal muscle size. Eur J Appl Physiol.
2004;91(1):116–8.
12. Chilibeck PD, Stride D, Farthing JP, Burke DG. Effect of creatine in-
gestion after exercise on muscle thickness in males and females.
Med Sci Sports Exerc. 2004;36(10):1781–8.
13. Abe T, DeHoyos DV, Pollock ML, Garzarella L. Time course for
strength and muscle thickness changes following upper and
lower body resistance training in men and women. Eur J Appl
Physiol. 2000;81(3):174–80.
14. Sanada K, Kearns CF, Midorikawa T, Abe T. Prediction and valida-
tion of total and regional skeletal muscle mass by ultrasound in
Japanese adults. Eur J Appl Physiol. 2006;96(1):24–31.
15. Feiereisen P, Vaillant M, Eischen D, Delagardelle C. Isokinetic ver-
sus one-repetition maximum strength assessment in chronic
heart failure. Med Sci Sports Exerc. 2010;42(12):2156–63.
16. Lusk SJ, Hale BD, Russell DM. Grip width and forearm orientation
effects on muscle activity during the lat pull-down. J Strength
Cond Res. 2010;24(7):1895–900.
17. Gentil P, Bottaro M. Influence of supervision ratio on muscle ad-
Gentil P et al.
5
Asian J Sports Med. 2015;6(1):e24057
aptations to resistance training in nontrained subjects. J Strength
Cond Res. 2010;24(3):639–43.
18. Schoenfeld BJ. The mechanisms of muscle hypertrophy and
their application to resistance training. J Strength Cond Res.
2010;24(10):2857–72.
19. Schoenfeld BJ. Does exercise-induced muscle damage play
a role in skeletal muscle hypertrophy? J Strength Cond Res.
2012;26(5):1441–53.
20. Eyler AA, Matson-Koffman D, Vest JR, Evenson KR, Sanderson B,
Thompson JL, et al. Environmental, policy, and cultural factors
related to physical activity in a diverse sample of women: The
Women's Cardiovascular Health Network Project--summary and
discussion. Women Health. 2002;36(2):123–34.
21. Trost SG, Owen N, Bauman AE, Sallis JF, Brown W. Correlates of
adults' participation in physical activity: review and update. Med
Sci Sports Exerc. 2002;34(12):1996–2001.
22. Schutzer KA, Graves BS. Barriers and motivations to exercise in
older adults. Prev Med. 2004;39(5):1056–61.
23. Silliman K, Rodas-Fortier K, Neyman M. A survey of dietary
and exercise habits and perceived barriers to following a
healthy lifestyle in a college population. Cal J Health Promot.
2004;18:281.
24. Takada S, Okita K, Suga T, Omokawa M, Kadoguchi T, Sato T, et al.
Low-intensity exercise can increase muscle mass and strength
proportionally to enhanced metabolic stress under ischemic
conditions. J Appl Physiol (1985). 2012;113(2):199–205.
25. Schott J, McCully K, Rutherford OM. The role of metabolites in
strength training. II. Short versus long isometric contractions.
Eur J Appl Physiol Occup Physiol. 1995;71(4):337–41.
26. Hornberger TA, Esser KA. Mechanotransduction and the regu-
lation of protein synthesis in skeletal muscle. Proc Nutr Soc.
2004;63(2):331–5.
  • ... General recommendations postulate that RT sessions should involve both multi-joint (MJ) and singlejoint (SJ) exercises, where the MJ exercise involve more than one joint acting dynamically and target several muscle groups at a time, whereas the SJ exercise involve one joint acting dynamically and target a primary muscle group (1). Although some studies support this recommendation and have demonstrated greater increases in arm circumference with combined MJ plus SJ exercises (5,7), others have challenged this suggestion showing that MJ and SJ exercises promote similar gains in muscle strength and hypertrophy in untrained individuals (15) and that the addition of SJ exercises to MJ exercises does not elicit additional muscular adaptations in untrained (16) or trained individuals (6,11) or even bodybuilders (4). ...
    ... A number of points, however, need to be considered in the interpretation of the aforementioned results. Some studies assessed muscle thickness of the elbow flexors with B-mode ultrasound (15,16), whereas others used arm circumference measurements (4)(5)(6)(7)11). Because all studies were conducted involving exercises for both flexor and extensor muscles of the elbow joint and circumference measures are not able to separately discriminate the increase in the size of these muscles, it remains inconclusive as to the isolated and combined effects of MJ and SJ exercises on muscle hypertrophy when assessed by magnetic resonance imaging (MRI), which has high reliability values (i.e., coefficient of variation [CV] ,1%) and is considered the gold-standard assessment of whole muscle cross-sectional area (CSA) (29). ...
    ... Discrepancies in these findings may be attributed to the used testing protocol. Specifically, Gentil et al. (15) showed similar increases in strength between MJ and SJ using a nonspecific test (isokinetic dynamometer), whereas Paoli et al. (28) found a strength advantage for MJ exercise when using a specific test (1-RM test for the same exercise used for the MJ protocol). There is evidence that the results of isokinetic and 1-RM tests are not equivalent (14) and that RT-induced strength gains are predicated on the specificity principle (21,23). ...
    Article
    Brandão, L, de Salles Painelli, V, Lasevicius, T, Silva-Batista, C, Brendon, H, Schoenfeld, BJ, Aihara, AY, Cardoso, FN, de Almeida Peres, B, and Teixeira, EL. Varying the order of combinations of single- and multi-joint exercises differentially affects resistance training adaptations. J Strength Cond Res XX(X): 000-000, 2020-Our study aimed to compare the effects of multi-joint (MJ) and single-joint (SJ) exercises, either isolated or in combination, and in different orders, on cross-sectional area (CSA) of the pectoralis major (PM) and different heads of the triceps brachii (TB), as well as on the one-repetition maximum (1-RM) in the bench press and lying barbell triceps press. Forty-three young men were randomly assigned to one of 4 possible RT protocols: barbell bench press plus lying barbell triceps press (MJ + SJ, n = 12); lying barbell triceps press plus barbell bench press (SJ + MJ, n = 10); barbell bench press (MJ, n = 10); or lying barbell triceps press (SJ, n = 11). Results showed significant within-group increases in 1-RM bench press for MJ, MJ + SJ, and SJ + MJ but not for SJ. Conversely, significantly greater within-group increases in elbow extension 1-RM were noted for SJ, MJ + SJ, and SJ + MJ but not for MJ. Significantly greater increases in PM CSA were observed for MJ, MJ + SJ, and SJ + MJ compared with SJ. Significant increases in TB CSA were noted for SJ, MJ + SJ, and SJ + MJ, but not for MJ, without observed between-group differences. Individual analysis of TB heads showed significantly greater CSA increases in the lateral head for MJ, MJ + SJ, and SJ + MJ compared with SJ. Alternatively, significantly greater increases in the long head were observed for SJ, MJ + SJ, and SJ + MJ compared with MJ. CSA increases for the medial head were statistically similar between conditions. Our findings indicate that muscular adaptations are differentially affected by performance of MJ and SJ exercises.
  • ... Specifically regarding the comparison between SJ and MJ exercises, Paoli et al. [7] demonstrated the superiority of RT containing only MJ in comparison with those containing only SJ in muscle strength gains and improvements on cardiorespiratory fitness, but without significant differences in body composition. Earlier, Gentil et al. [8] found no difference in strength gains and hypertrophy in the elbow flexors in untrained men performing SJ or MJ exercises. However, in that study [8] the analysis of hypertrophy was limited to the upper limbs. ...
    ... Earlier, Gentil et al. [8] found no difference in strength gains and hypertrophy in the elbow flexors in untrained men performing SJ or MJ exercises. However, in that study [8] the analysis of hypertrophy was limited to the upper limbs. Considering that the responses to RT between the upper and lower limbs are different [9,10], it is necessary to investigate the effects of exercise selection in the lower body muscles, such as the quadriceps femoris and gluteus maximus. ...
    ... Another important point is that the only study that compared muscle hypertrophy between SJ and MJ exercises was performed in men [8]. Previous studies have suggested that men and women respond differently to RT in muscle recovery [16], fatigability [17] and muscle activation [18][19][20], which necessitates performing specific studies in females. ...
    Article
    The study compared the effects of back squat (BS) and hip thrust (HT) exercises on muscle strength and hypertrophy in well-trained women. Twenty-two participants were divided in two groups: BS group (n=12, 26.4±1.32 years, 171.8±3.79 cm, and 69.5±4.9 kg) performed the BS exercise and HT group (n=10, 27.5±1.42 years, 170.8±4.4 cm, 67.5±4.7 kg) performed the HT exercise. Training was performed for 12 weeks. Before and after the training period, participants were assessed for quadriceps femoris and gluteus maximus muscle thickness (MT) and 1 repetition maximum (1RM) test on the BS and HT. Both groups significantly increased hip extensors MT and HT 1RM; however, the improvements in BS group were higher than in HT group on quadriceps femoris (12.2% for BS and 2% for HT, P<0.001) and gluteus maximus MT (9.4% for BS and 3.7% for HT, P=0.001) and BS 1 RM (35.9% for BS and 4.3% for HT, P<0.001). BS was more efficient than HT, since it resulted in greater muscle hypertrophy of the quadriceps femoris and gluteus maximus, increases in BS 1RM and similar increases in HT.
  • ... Furthermore, it is often believed that within this population performing SJ exercises may bring further benefits to adaptation of specific muscle groups [5][6][7]. However, previous studies showed that SJ exercises do not appear to bring superior increases in muscle size and strength when compared to MJ [8]. Other studies have shown that the addition of SJ exercises ...
    ... It is important to remember that the present study did not specifically evaluate the effect of adding SJ to MJ, but its concomitant use, making it difficult to compare with previous studies. However, our findings are in agreement with Gentil et al. [8] which found similar increases in muscle thickness for biceps brachii between MJ and SJ in untrained men and also to Paoli et al. [14] that suggest that performing MJ exercises results in higher increases in muscle strength in MJ exercises than performing SJ. ...
    Article
    The study compared the effects of resistance training programs composed by multi-joint (MJ), single-joint (SJ) and the combination of multi- and single-joint (MJ+SJ) exercises on muscle strength and hypertrophy in trained women. Thirty participants were divided into groups that performed only MJ exercises, SJ exercises and MJ+SJ exercises for six months. Participants were tested for 1-repetition maximum (RM) and muscle thickness (MT) before and after the intervention. All groups showed significant gains on 1RM tests from pre- to post-training (P<0.01). However, MJ and MJ+SJ groups obtained greater gains in 1RM for the MJ exercises in comparison with the SJ group. Increases in 1RM for the SJ exercises were similar among groups, with the exception of leg curl, where the SJ group obtained greater gains than MJ and MJ+SJ. All groups obtained significant increases in MT from pre- to post-training for all muscle groups. However, MJ and MJ+SJ groups presented greater increases in gluteus maximus, quadriceps femoris and pectoralis major in comparison with the SJ group. Therefore, our results suggest that, in general, performing MJ exercises seems to be necessary to obtain optimal results from a resistance training program; however SJ might be necessary to provide optimal strength gains in knee flexion.
  • ... multiple-joint, 4) stable vs. unstable surface, 5) open vs. closed kinetic chain, and 6) flat vs. incline (2). Several studies have been conducted in order to evaluate the effects of exercise choice on neuromuscular adaptations to resistance training (12)(13)(14). However, there is a paucity of studies comparing the chronic adaptations to resistance training when the same exercise is performed at different angles (e.g., supine or incline position). ...
    Article
    International Journal of Exercise Science 13(6): 859-872, 2020. The aim of the current study was to investigate the effects of horizontal and incline bench press as well as the combination of both exercises on neuromuscular adaptation in untrained young men. Forty-seven untrained men were randomly assigned to one of the three groups: 1) a horizontal bench press group (n= 15), 2) an incline bench press group (n= 15), and 3) a combination (horizontal + incline) group (n= 17). Training was conducted once a week for eight weeks, with equalized number of sets among groups. Muscle thickness, isometric strength and electromyography (EMG) amplitude of the pectoralis major were measured one week before and after the training period. There was no difference between groups for the change in horizontal bench press isometric strength (~ 10 kg increase, p=0.776) or incline bench press isometric strength (~ 11 kg increase, p=0.333). Changes in muscle thickness differed only in one of the three sites. The changes in the second intercostal space of the pectoralis major was greatest in the incline pressure group compared with the horizontal [mean difference (95% CI) of 0.62 (0.23, 1.0) cm, p=0.003] and combination groups [mean difference (95% CI) of 0.50 (0.14, 0.86) cm, p=0.008]. The change in EMG amplitude following training differed between groups in only one out of the four sites. The present results indicate that strength and conditioning professionals might consider that horizontal and incline bench press exercises, or a combination of both exercises can render similar change in general strength.
  • ... It should also be done in order to avoid injuries since it essentially helps muscle elasticity and smoothens muscular contractions (Safran, Seaber & Garrett, 1989;Woods, Bishop & Jones, 2007). An exercise program should start on multi-joint movements before progressing to single-joint movements to maximize muscle strength (Dahab & McCambridge, 2009;Gentil Soares & Bottaro, 2015). ...
    Preprint
    Full-text available
    The aim of the study was to understand the possible association between calisthenics and sustained attention through a quasi-experimental research. The study was done in order to help give a possible solution on certain problems brought about by extended gadget time to students. In the study, 12-18 years old male high-school participants (n=21) were randomly assigned to an experimental group (EG) or a control group (CG). The amount of physical activity of the CG was limited to P.E. class and recreational activities while the EG were given a 4-week calisthenics training program atop the aforementioned activities. A Deary-Liewald Choice Reaction Time (CRT) task, the tool used to measure sustained attention, was conducted prior to (pretest) and after the calisthenics program. The two components of sustained attention, response accuracy (CC) and processing speed (CMRT), were collected from the CRT task and examined. The findings indicate that calisthenics has a possible effect on sustained attention because a significant improvement was seen on the posttest score of the EG in terms of response accuracy while no improvement was found on the CG. In terms of processing speed, no significant difference was found on either group.
  • ... La selección de ejercicios para el entrenamiento de la fuerza depende de factores como la disponibilidad de equipos, la especificidad del movimiento, las preferencias individuales y el compromiso de tiempo (Gentil, Soares y Bottaro, 2015). Sin embargo, es necesario complementar los métodos tradicionales de entrenamiento de fuerzas verticales (sentadillas, peso muerto, zancadas estáticas, etc.) con ejercicios de fortalecimiento de patrón horizontal (como glute bridge y hip thrusts) (marchante, 2015), debido a que el trabajo específico del glúteo favorecerá la prevención de lesiones y dolor, así como el aumento de la transferencia de fuerza (contreras, 2014). ...
    Article
    Full-text available
    Resumen Este artículo de investigación presenta los resultados de un estudio que consistió en determinar la relación entre la repetición máxima en ejercicios accesorios y el peso muerto rumano en sujetos con experiencia en el entrenamiento de la fuerza con sobrecargas. Para ello, se realizó un estudio exploratorio de tipo correlacional con enfoque cuantitativo y una muestra a conveniencia de 12 hombres sanos (edad 20,37 ± 5,28, talla 1,72 ± 0,12 m, peso 65,92 ± 14,06 kg, imc 22,98 ± 3,93 kg/m 2) capacitados en el entrenamiento de la fuerza con sobrecargas. Se llevó a cabo el test de repetición máxima con los ejercicios: peso muerto rumano, remo con barra, bíceps con barra, jalón a la cara en polea, encogimientos con barra, curl femoral acostado y empuje de cadera). Los datos se analizaron en el paquete estadístico ibm spss v.22 con un nivel de confianza del 95 % y un p-valor de 0,05, se aplicaron la prueba de normalidad de Shapiro-Wilk y el coeficiente correlacional de Pearson. Los resultados obtenidos evidenciaron una distribución normal de la repetición máxima de los ejercicios (p > 0,05) y una relación muy significativa entre la repetición máxima del empuje de cadera y el peso muerto rumano (r = 0,89, p < 0,01). Teniendo en cuenta esta relación, el empuje de cadera en la planificación del entrenamiento de la fuerza con sobrecargas ayudará a incrementar la repetición máxima en el peso muerto rumano. Palabras clave: entrenamiento de la fuerza; fuerza máxima; peso muerto rumano; repetición máxima
  • Article
    Full-text available
    Resistance training (RT) is a popular exercise mode and is considered an essential part of an exercise program. In current pandemic times due to the coronavirus (i.e. COVID-19) outbreak, RT practice has been strongly threatened. However, such threat might not be an inherent problem to RT, but rather to misconceptions related to RT. In the current opinion article, we provide insights to better understand RT. When analyzing current scientific evidence, it seems that RT can be performed in a safe, time-efficient and uncomplicated manner, in many different places and with few resources, which makes it fully feasible within measures adopted to control coronavirus dissemination. RT should not be sacrificed due to consequences of the coronavirus pandemic. However, it might be necessary to sacrifice some old-fashioned thoughts, rooted in beliefs that have already been overturned by science. It would be counter-productive for population health (and countries economy) to avoid RT due to the misconception that specialized equipment, fashioned programs, or resources are needed for effective programs implementation. Therefore, RT can be easily adapted to the new time and logistical challenges brought by the coronavirus outbreak. From a practical standpoint, RT could be performed using body weight, accessible materials (e.g. elastic bands, lights dumbbells and barbell) or even without external load at home or at public spaces and still result in important health benefits.
  • Article
    Full-text available
    Kipp, K, Kim, H, and Wolf, WI. Muscle forces during the squat, split squat, and step-up across a range of external loads in college-aged men. J Strength Cond Res XX(X): 000-000, 2020-Knowledge about the load-dependent demand placed on muscles during resistance training exercises is important for injury prevention and sports performance training programs. The purpose of this study was to investigate the effect of external load on lower extremity muscle forces during 3 common resistance training exercises. Nine healthy subjects performed 4 sets of the squat (SQ), split squat (SS), and step-up (SU) exercises each with 0, 25, 50, and 75% of body mass as additional load. Motion capture and force plate data were used to estimate individual muscle forces of 11 lower extremity muscles through static optimization. The results suggest load-dependent increases in muscle forces for the m. gluteus maximus, m. gluteus medius, vastus lateralis, m. vastus medius, m. vastus intermedius, m. semitendinosus, m. semimembranosus, m. biceps femoris long head, m. soleus, m. gastrocnemius lateralis, and m. gastrocnemius medialis during the execution of all 3 exercises. In addition, load-dependent increases in m. gluteus maximus, vastus lateralis, m. vastus medius, m. vastus intermedius, and m. biceps femoris long head forces were often more pronounced during the SS and SU than the SQ across the range of loads used in this study. These results suggest that the mechanical demands imposed by resistance training exercises scale with external load and that the extent of that scaling depends on the specific exercise.
  • Article
    Full-text available
    Resistance-training of the lower limbs can be performed using exercises moving one (single-joint exercises) or several joints (multi-joint exercises). This study compared the effects of training one multi-joint exercise (leg press) or two single-joint exercises (leg extension and kickback) on dynamic and isometric strength and the transferability of dynamic strength between exercises. Fifty-three physically active women were randomized to a multi-joint (MJ) training group (age = 21.95±0.82 years, mass = 64.85±5.76 kg, height = 167.35±2.47 cm; n = 20), single-joint (SJ) training group (age = 22.56±1.66 years, mass = 64.85±5.76 kg, height = 165.94±2.84 cm; n = 18), or a control (CON) group (age = 21.27±0.68 years, mass = 68.43±4.86 kg, height = 168.63±2.84 cm; n = 15). The training groups participated in an 8-week supervised single- or multi-joint lower limb training consisting of 18 sessions. Pre- and post-training, six repetitions maximum (RM) and maximal voluntary isometric contraction in the three exercises were assessed, along with electromyography of the superficial quadriceps muscles. Improvements in all dynamic exercises were greatest after training the specific exercises (ES = 1.26–2.14, P<0.001–0.025) and all were greater in the training groups than in the CON group (ES = 1.43–3.31, P<0.001–0.021). The SJ group improved 6RM in leg extension and kickback more than leg press (ES = 1.51 and 2.04, respectively, P<0.001), whereas the MJ group improved leg press 6RM more than kickback (ES = 1.10, P = 0.002). However, leg press and leg extension strength improved similarly in the MJ group (ES = 0.54, P = 0.072). All strength and electromyographic measures remained unchanged in the CON group (ES = 0.00–0.44, P = 0.412–0.966). Improved dynamic strength in leg press, kickback and leg extension is best attained by training the specific exercises, but both training modalities can improve strength across all exercises.
  • Thesis
    Une nouvelle méthode de musculation, appelée méthode 3/7, consistant à réaliser 5 séries en escalier (de 3 à 7 répétitions) avec une charge de 70 % d’une répétition maximale (1RM) espacées d’un temps de récupération court (15 secondes) s’avère plus efficace pour augmenter la force musculaire qu’une méthode classique (à nombre de répétitions constant) avec un temps de récupération long (150 secondes ; Laurent et coll., 2016). L’intérêt de cette méthode est de combiner l’utilisation de charges modérées tout en induisant une réponse métabolique importante (Penzer et coll., 2016). Au regard du gain de temps que procure cette méthode, elle pourrait être intégrée dans la préparation physique de sportifs, mais également de personnes prises en charge dans le cadre d’une revalidation.Dès lors, l’objectif général de ce travail de thèse a été d’étudier l’efficacité de la méthode 3/7 sur les gains de force et sur les adaptations musculaires et plus spécifiquement de mieux comprendre les facteurs responsables de celle-ci. A cet effet, trois principaux projets ont été élaborés. Le premier avait pour objectif d’optimiser l’efficacité de la méthode 3/7 en investiguant les gains de force maximale, ainsi que les adaptations neurophysiologiques et musculaires sous-jacentes suite à 12 semaines d’entrainement des muscles fléchisseurs du coude. Lors du deuxième projet, l’effet aigu de la méthode 3/7 sur les dommages musculaires, les réponses inflammatoires, hormonales, et métaboliques y compris celles sur le stress oxydant a été évalué à la suite d’une séance de renforcement musculaire composée de quatre exercices (le développé couché, l’extension de jambes à la presse inclinée, le tirage horizontal et la flexion plantaire). Enfin, le troisième projet a permis de suivre l’évolution des réponses biochimiques aigües, des adaptations musculaires et des adaptations nerveuses, ainsi que de la force suite à cette méthode au cours de 22 séances d’entrainement composées des mêmes exercices que ceux du projet 2. Lors de nos 3 projets, la méthode 3/7 a toujours été comparée à une méthode dite classique à charge constante et de volume de travail total similaire mais avec une récupération plus longue (méthode 8x6).Les gains de force maximale ont été déterminés par des contractions volontaires maximales isométriques (CVMI) et la charge maximale mobilisée, lors de 1RM ou de 3RM. L’évolution des paramètres neurophysiologiques a principalement été étudiée par l’activité électromyographique (EMG), l’onde motrice maximale (Mmax) ainsi que le niveau d’activation volontaire maximale (AV). Pour les paramètres biochimiques, nous avons réalisé des analyses des marqueurs sanguins du stress oxydant, du stress métabolique, des dommages musculaires, de la réponse inflammatoire et de la réponse hormonale. Enfin, pour les paramètres musculaires, des mesures échographiques ont été effectuées, et l’évaluation de la masse maigre et de la masse grasse a été déterminée par absorption bi-photonique à rayons X. De plus, le niveau d’oxygénation tissulaire a été mesuré via spectrométrie proche de l’infrarouge.La méthode 3/7 a induit un déficit d’oxygénation plus important que la méthode 8x6 (Projet 1) entrainant une augmentation de lactate et de testostérone dans le sang immédiatement après la séance tandis que les témoins des dommages musculaires (créatine kinase et myoglobine) ont augmenté de manière similaire suite aux 2 méthodes (Projet 2 et 3). Le lactate agirait sur la production d’espèces oxygénées activées (EOA), d’interleukine-6, de cortisol et de l’hormone de croissance qui induiraient à leur tour une augmentation des leucocytes (Projets 2 et 3). La méthode 3/7 a amélioré l’AV sans différence avec la méthode 8x6 (Projet 3) mais a aussi entrainé des adaptations musculaires et amélioré la force maximale (Projet 1 et 3) même si cette méthode n’est pas systématiquement plus efficace que la méthode 8x6 (Projet 3). Il est également à noter que la capacité du sujet à pouvoir réaliser seul le volume de travail imposé par la méthode 3/7 influencerait les adaptations à l’entrainement (Projet 3).Il convient de souligner que l’évolution des paramètres biochimiques n’implique pas une relation directe de cause à effet sur les adaptations musculaires. De plus, le stress métabolique lors de la méthode 3/7 ne semble pas induire systématiquement un effet supplémentaire à la signalisation intramusculaire d’origine mécanique. La synthèse protéique myofibrillaire pourrait atteindre un niveau de saturation de la réponse anabolique suite à la signalisation intramusculaire d’origine mécanique. D’autre part, les divergences des résultats entre nos différents projets pourraient provenir des variabilités inter-individuelles. Les facteurs individuels intrinsèques seraient des déterminants plus importants pour développer la masse musculaire que les paramètres extrinsèques d’un programme d’entrainement. En conclusion, la méthode 3/7 induit des adaptations similaires ou plus importantes qu’une méthode classique (méthode 8x6) mais avec une durée d’entrainement 3 à 4 fois moindre.
  • Article
    Full-text available
    Training attendance is an important variable for attaining optimal results after a resistance training (RT) program, however, the association of attendance with the gains of muscle strength is not well defined. Therefore, the purpose of the present study is to verify if attendance would affect muscle strength gains in healthy young males. Ninety two young males with no previous RT experience volunteered to participate in the study. RT was performed 2 days a week for 11 weeks. One repetition maximum (1RM) in the bench press and knee extensors peak torque (PT) were measured before and after the training period. After the training period, a two step cluster analysis was used to classify the participants in accordance to training attendance, resulting in three groups, defined as high (92 to 100%), intermediate (80 to 91%) and low (60 to 79%) training attendance. According to the results, there were no significant correlations between strength gains and training attendance, however, when attendance groups were compared, the low training attendance group showed lower increases in 1RM bench press (8.8%) than the other two groups (17.6% and 18.0% for high and intermediate attendance, respectively). Although there is not a direct correlation between training attendance and muscle strength gains, it is suggested that a minimum attendance of 80% is necessary to ensure optimal gains in upper body strength.
  • Article
    The present study was performed to develop regression-based prediction equations for skeletal muscle (SM) mass by ultrasound and to investigate the validity of these equations in Japanese adults. Seventy-two Japanese men (n = 38) and women (n = 34) aged 18-61 years participated in this study and were randomly separated into two groups: the model development group (n = 48) and the validation group (n = 24). The total and regional SM mass were measured using magnetic resonance imaging (MRI) 1.5 T-scanners with spin- echo sequence. Contiguous transverse images (about 150 slices) with a slice thickness of 1 cm were obtained from the. first cervical vertebra to the ankle joints. The volume of SM was calculated from the summation of digitized cross-sectional area. The SM volume was converted into mass units (kg) by an assumed SM density of 1.04 kg l(-1). The muscle thickness (MTH) was measured by B-mode ultrasound (5 MHz scanning head) at nine sites on the anatomical SM belly. Strong correlations were observed between the site-matched SM mass (total, arm, trunk body, thigh, and lower leg) by MRI measurement and the MTH x height (in m) in the model development group (r = 0.83-0.96 in men, r = 0.53-0.91 in women, P < 0.05). When the SM mass prediction equations were applied to the validation group, significant correlations were also observed between the MRI-measured and predicted SM mass (P < 0.05). The predicted total SMmass for the validation group was 19.6 (6.5) kg and was not significantly different from the MRI-measured SM mass of 20.2 (6.5) kg. Bland-Altman analysis did not indicate a bias in prediction of the total SM mass for the validation group (r = 0.00, NS). These results suggested that ultrasound-derived prediction equations are a valid method to predict SM mass and an alternative to MRI measurement in healthy Japanese adults.
  • Article
    Full-text available
    The aim of this study was to examine the effect of adding single-joint (SJ) exercises to a multi-joint (MJ) exercise resistance-training program on upper body muscle size and strength. Twenty-nine untrained young men participated in a 10-week training session. They were randomly divided in 2 groups: the MJ group performed only MJ exercises (lat pulldown and bench press); the MJ+SJ group performed the same MJ exercises plus SJ exercises (lat pulldown, bench press, elbow flexion, and elbow extension). Before and after the training period, the muscle thickness (MT) of the elbow flexors was measured with ultrasound, and peak torque (PT) was measured with an isokinetic dynamometer. There was a significant (p < 0.05) increase in MT (6.5% for MJ and 7.04% for MJ+SJ) and PT (10.40% for MJ and 12.85% for MJ+SJ) in both groups, but there were no between-group differences. Therefore, this study showed that the inclusion of SJ exercises in a MJ exercise training program resulted in no additional benefits in terms of muscle size or strength gains in untrained young men.
  • Article
    Maximum strength is the capacity to generate force within an isometric contraction. It is a valuable attribute to most athletes because it acts as a general base that supports specific training in other spheres of conditioning. Resistance training program variables can be manipulated to specifically optimize maximum strength. After deciding on the exercises appropriate for the sport, the main variables to consider are training intensity (load) and volume. The other factors that are related to intensity are loading form, training to failure, speed of contraction, psychological factors, interset recovery, order of exercise, and number of sessions per day. Repetitions per set, sets per session, and training frequency together constitute training volume. In general, maximum strength is best developed with 1-6 repetition maximum loads, a combination of concentric and eccentric muscle actions, 3-6 maximal sets per session, training to failure for limited periods, long interset recovery time, 3-5 days of training per week, and dividing the day's training into 2 sessions. Variation of the volume and intensity in the course of a training cycle will further enhance strength gains. The increase in maximum strength is effected by neural, hormonal, and muscular adaptations. Concurrent strength and endurance training, as well as combination strength and power training, will also be discussed. (C) 1999 National Strength and Conditioning Association
  • Article
    The authors assessed the diet and exercise habits and perceived barriers to following a healthy lifestyle of 471 college students. Sixty percent of the participants were female and 31% had BMIs > 25. Breakfast was the most commonly missed meal and 63% of students snacked one to two times per day. Fifty-eight percent of participants ate vegetables and 64% ate whole or canned fruit less than once per day. Men consumed more soda and alcohol and used higher fat dairy, ate more meat, and ate fewer vegetables and fruits than women. Over half of the subjects rated their diet as poor or fair with "lack of time" listed as the number one barrier to eating well. Men exercised more frequently and at greater intensity than women and were more confident with their body image. The most common barrier to exercise was "lack of time." The results of this study have implications for the design of general and specific diet and physical activity interventions among college students.
  • Article
    Full-text available
    Skeletal muscle bulk and strength are becoming important therapeutic targets in medicine. To increase muscle mass, however, intensive, long-term mechanical stress must be applied to the muscles, and such stress is often accompanied by orthopedic and cardiovascular problems. We examined the effects of circulatory occlusion in resistance training combined with a very low-intensity mechanical load on enhancing muscular metabolic stress and thereby increasing muscle bulk. Muscular metabolic stress, as indicated by the increases in inorganic phosphate (P(i)) and a decrease in intramuscular pH, was evaluated by (31)P-magnetic resonance spectroscopy during unilateral plantar-flexion at 20% of the one-repetition maximum (1-RM) with circulatory occlusion for 2 min in 14 healthy, male untrained participants (22 yr) at baseline. Participants performed two sets of the same exercise with a 30-s rest between sets, 2 times/day, 3 days/wk, for 4 wk. The muscle cross-sectional area (MCA) of the plantar-flexors and the 1-RM were measured at baseline and after 2 and 4 wk of training. MCA and 1-RM were significantly increased after 2 and 4 wk (P < 0.05, respectively). The increase in MCA at 2 wk was significantly (P < 0.05) correlated with the changes in P(i) (r = 0.876) and intramuscular pH (r = 0.601). Furthermore, the increases in MCA at 4 wk and 1-RM at 2 wk were also correlated with the metabolic stress. Thus enhanced metabolic stress in exercising muscle is a key mechanism for favorable effects by resistance training. Low-intensity resistance exercise provides successful outcomes when performed with circulatory occlusion, even with a short training period.
  • Article
    Full-text available
    Exercise-induced muscle damage (EIMD) occurs primarily from the performance of unaccustomed exercise, and its severity is modulated by the type, intensity, and duration of training. Although concentric and isometric actions contribute to EIMD, the greatest damage to muscle tissue is seen with eccentric exercise, where muscles are forcibly lengthened. Damage can be specific to just a few macromolecules of tissue or result in large tears in the sarcolemma, basal lamina, and supportive connective tissue, and inducing injury to contractile elements and the cytoskeleton. Although EIMD can have detrimental short-term effects on markers of performance and pain, it has been hypothesized that the associated skeletal muscle inflammation and increased protein turnover are necessary for long-term hypertrophic adaptations. A theoretical basis for this belief has been proposed, whereby the structural changes associated with EIMD influence gene expression, resulting in a strengthening of the tissue and thus protection of the muscle against further injury. Other researchers, however, have questioned this hypothesis, noting that hypertrophy can occur in the relative absence of muscle damage. Therefore, the purpose of this article will be twofold: (a) to extensively review the literature and attempt to determine what, if any, role EIMD plays in promoting skeletal muscle hypertrophy and (b) to make applicable recommendations for resistance training program design.