Different Patterns in Muscular Strength and Hypertrophy Adaptations in Untrained Individuals Undergoing Non-Periodized and Periodized Strength Regimens

Abstract

This study investigated the effects of non-periodized (NP), traditional periodization (TP) and daily undulating (UP) regimens on muscle strength and hypertrophy in untrained individuals. Thirty-three recreationally active males were randomly divided into four groups: NP: n = 8; TP: n = 9; UP: n = 8 and control group (C): n = 8. Experimental groups underwent a 12-week strength-training program consisting of two sessions per week. Muscle strength and quadriceps cross-sectional area (QCSA) were assessed at baseline, 6-wk (i.e. mid-point) and after 12-wk. All training groups increased squat 1RM from pre to 6-wk mid (NP: 17.02%, TP: 7.7% and UP: 12.9%, p≤0.002) and pre to post 12-wk (NP: 19.5%, TP: 17.9% and UP: 20.4%). TP was the only group that increased squat 1RM from 6-wk mid to 12-wk period (9.4%, p≤0.008). All training groups increased QCSA from pre to 6-wk mid (NP: 5.1%, TP: 4.6% and UP: 5.3%, p≤0.0006) and from pre to post 12-wk (NP: 8.1%, TP: 11.3% and UP: 8.7%). From 6-wk mid to 12-wk period, TP and UP were the only groups that increased QCSA (6.4% and 3.7%, p≤0.02). There were no significant changes for all dependent variables in C group across the time (p≥0.05). In conclusion, our results demonstrated similar training-induced adaptations after 12-wk of NP and periodized regimens. However, our findings suggest that in the latter half of the study (i.e. after the initial 6 weeks), the periodized regimens elicited greater rates of muscular adaptations compared to NP. Strength coaches and practitioners should be aware that periodized regimens might be advantageous at latter stages of training even for untrained individuals.

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DIFFERENT PATTERNS IN MUSCULAR STRENGTH AND
HYPERTROPHY ADAPTATIONS IN UNTRAINED
INDIVIDUALS UNDERGOING NONPERIODIZED AND
PERIODIZED STRENGTH REGIMENS
EDUARDO O. DESOUZA,
1
VALMOR TRICOLI,
2
JACOB RAUCH,
1
MICHAEL R. ALVAREZ,
1
GILBERTO LAURENTINO,
1
ANDRE
´Y. AIHARA,
3
FABIANO N. CARDOSO,
3
HAMILTON ROSCHEL,
2,4
AND
CARLOS UGRINOWITSCH
2
1
Department of Health Science and Human Performance, University of Tampa, Tampa, Florida;
2
Department of Physical
Education and Sport, Laboratory of Adaptations to Strength Training, University of Sa˜o Paulo, Sa˜o Paulo, Brazil;
3
America’s
Diagnostic S/A, Sa˜o Paulo, Sa˜o Paulo, Brazil; and
4
Applied Physiology and Nutrition Research Group, Department of
Physical Education and Sport, University of Sa˜o Paulo, Sa˜o Paulo, Brazil
ABSTRACT
De Souza, EO, Tricoli, V, Rauch, J, Alvarez, MR, Laurentino, G,
Aihara, AY, Cardoso, FN, Roschel, H, and Ugrinowitsch, C.
Different patterns in muscular strength and hypertrophy adapta-
tions in untrained individuals undergoing non-periodized and
periodized strength regimens. JStrengthCondRes32(5):
1238–1244, 2018—This study investigated the effects of nonper-
iodized (NP), traditional periodization (TP), and daily undulating
periodization (UP) regimens on muscle strength and hypertrophy
in untrained individuals. Thirty-three recreationally active males
were randomly divided into 4 groups: NP: n=8;TP:n=9;
UP: n=8,andcontrolgroup(C):n=8.Experimentalgroups
underwent a 12-week strength training program consisting of 2
sessions per week. Muscle strength and quadriceps
cross-sectional area (QCSA) were assessed at baseline, 6 weeks
(i.e., mid-point) and after 12 weeks. All training groups increased
squat 1RM from pre to 6 weeks mid (NP: 17.02%, TP: 7.7%, and
UP: 12.9%, p#0.002) and pre to post 12 weeks (NP: 19.5%,
TP: 17.9%, and UP: 20.4%, p#0.0001). Traditional periodiza-
tion was the only group that increased squat 1RM from 6 weeks
mid to 12-week period (9.4%, p#0.008). All training groups
increased QCSA from pre to 6 weeks mid (NP: 5.1%, TP:
4.6%, and UP: 5.3%, p#0.0006) and from pre to post 12 weeks
(NP: 8.1%, TP: 11.3%, and UP: 8.7%, p#0.0001). From 6
weeks mid to 12-week period, TP and UP were the only groups
that increased QCSA (6.4 and 3.7%, p#0.02). There were no
significant changes for all dependent variables in C group across
the time (p$0.05). In conclusion, our results demonstrated sim-
ilar training-induced adaptations after 12 weeks of NP and perio-
dized regimens. However, our findings suggest that in the latter
half of the study (i.e., after the initial 6 weeks), the periodized
regimens elicited greater rates ofmuscularadaptationscompared
with NP regimens. Strength coaches and practitioners should be
aware that periodized regimens might be advantageous at latter
stages of training even for untrained individuals.
KEY WORDS periodization, strength training, muscle cross-
sectional area
INTRODUCTION
Strength training (ST) is widely used to increase
muscular strength and mass (i.e., hypertrophy)
across different populations (3,6,12,24). In this re-
gard, the systematic manipulation of ST-related
variables (i.e., training periodization) has been advocated
to optimize training-induced adaptations (1).
Although there are several periodization models that can be
used during an ST program, it is possible to pinpoint the 2 most
common ones. Traditional periodization (TP) consists of
increasing intensities and decreasing volumes throughout the
training period, whereas undulating periodization (UP) is
characterized by alternating high-volume low-intensity with
low-volume high-intensity training sessions during training (1).
Several studies have suggested that periodized models
(e.g., TP and UP) optimize strength gains when compared
with nonperiodized (NP) regimens (NP—i.e., constant inten-
sity and volume) (1,14,17,23,29). However, when volume
load was equated, the few studies that have compared perio-
dized and NP models did not report superior strength gains
between training regimens (8,18,22).
Concerning muscle hypertrophy (i.e., increase in cross-
sectional area—cross-sectional area [CSA]), despite a paucity
Address correspondence to Dr. Eduardo O. De Souza, edesouza@ut.edu.
32(5)/1238–1244
Journal of Strength and Conditioning Research
!2018 National Strength and Conditioning Association
1238
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of data on the effects of different periodization and NP regi-
mens on muscle mass accrual, the alleged benefits of periodized
training on muscle hypertrophy have been recently challenged
(8,15,16,21,22,26). In fact, only De Souza et al. (2014) investi-
gated the effects of TP and UP schemes compared with NP
using a gold standard assessment to detect changes on muscle
CSA. The authors found similar improvements on muscle
hypertrophy (;4.96%) between groups after 6 weeks of volume
load–equated protocols (22). However, the short time frame of
the training protocol does not allow further conclusions to be
drawn on how NP and periodized regimens modulate muscle
hypertrophy in untrained individuals over longer periods of
time.
Therefore, the purpose of this study was to investigate the
effects of NP, TP, and UP training regimens on muscle
strength and hypertrophy in recreationally active male
college students. We hypothesized that the ST-induced
adaptations would demonstrate a similar pattern between
experimental groups.
METHODS
Experimental Approach to the Problem
This was a randomized, parallel-group repeated-measures
design, which investigated the effects of 3 different ST
regimens (NP, TP, and UP) on maximum strength adapta-
tions and quadriceps cross-sectional area (QCSA) in recrea-
tionally active male college students. All experimental groups
trained 2 times a week for 12 weeks. The total number of sets
and repetitions was equated between groups, whereas training
intensity was manipulated differently across training groups
throughout the experimental period. Maximum strength and
QCSA were assessed at baseline (pre), after 6 weeks (6 weeks),
and after 12 weeks (12 weeks) of training by means of back
squat 1RM and magnetic resonance imaging (MRI) of the
quadriceps muscle, respectively.
Subjects
Forty-one recreationally active male college students (age
range: 19 to 33 years) engaged in sports such as soccer,
volleyball, and basketball, but not undergoing regular
strength and endurance training for at least 6 months before
the experimental period volunteered for this study. Partic-
ipants were stratified based on their pretest QCSA (e.g., CSA
[mm
2
]). Afterward, participants were randomly assigned to
the experimental groups. Participants were free from health
problems and/or neuromuscular disorders that could affect
their ability to complete the training protocols. In addition,
they were instructed to maintain their normal diet, refrain
from taking any nutritional supplements, and endure exer-
cise throughout the study period. After the initiation of the
experimental protocol, 8 participants withdrew because of
personal reasons (Table 1), thus data from 33 subjects were
included in the statistical analysis. All participants were
informed of the inherent risks and benefits before signing
a written informed consent form. The current study was
approved by the School of Physical Education Review Board
of University of Sa
˜o Paulo. Table 1 shows participants’ main
characteristics.
Procedures
Familiarization Sessions. All participants completed 3 famil-
iarization sessions interspersed by a minimum of 72 hours
before the commencement of the study. During the famil-
iarization sessions, participants performed a general warm-
up consisting of 5 minutes of running at 9 km$h
21
on
a treadmill (Movement Technology, Brudden, Sa
˜o Paulo,
Brazil) followed by 3 minutes of whole-body light stretch-
ing exercises. After warm-up, participants were familiarized
with the back squat exercise 1RM testing protocol. Individ-
uals were considered acquainted to the 1RM test if the
coefficient of variation (CV) between familiarization ses-
sions 2 and 3 was lower than 5%. Body position and foot
placement were determined with measuring tapes fixed on
the bar and on the ground, respectively. In addition,
a wooden seat with adjustable heights was placed behind
the subject to keep the bar displacement and knee flexion
angle (;908) constant on each squat repetition. Partici-
pants’ positioning was recorded during the familiarization
TABLE 1. Participants’ characteristics.*†
Variable C NP TP UP
N8898
Age (yrs) 25.1 63.3 25.6 66.3 25.0 67.0 24.4 65.2
Height (cm) 173.6 66.8 172.8 66.1 175.3 65.7 176.8 65.3
Body mass (kg) 76.8 611.7 79.5 613.0 76.0 69.9 74.9 64.2
1RM (kg) 126.8 621.3 140.7 623.9 141.1 619.7 149.5 634.6
CSA (mm
2
) 8,913.3 61,041.9 8,801.4 6983.8 8,738.9 6770.8 8,407.6 61,449.0
*C = control group; NP = nonperiodized; TP = traditional periodized; UP = daily undulating periodized; 1RM = one repetition
maximum; CSA = cross-sectional area.
†Data are mean 6SD.
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sessions and reproduced throughout the study. The CV
between familiarization maximum dynamic strength assess-
ments was 3.4%.
Maximum Dynamic Strength Test (1RM). After the familiariza-
tion procedures (i.e., 72 hours after the last familiarization
session), lower limb 1RM was assessed using the back squat
exercise on a conventional Smith machine (Portico; Sa
˜oPaulo,
Brazil). Testing protocol followed previous recommendations
(4). Participants had up to 5 attempts to achieve their 1RM load
(i.e., the maximum weight that could be lifted once with the
proper technique) with a 3-minuteintervalbetweentrials.Each
lift was deemed successful if participants touched their buttocks
on the wooden seat at the end of the eccentric phase and fully
extended their lower limb joints at the end of the concentric
phase of the lift.
Muscle Cross-Sectional Area. Dominant leg QCSA was
obtained through MRI (Signa LX 9.1; GE Healthcare,
Milwaukee, WI, USA). Leg dominance was determined
by asking the participants the preferred leg to kick a ball.
Participants laid on the device in a supine position with
their knees extended. Velcro straps were used to restrain
leg movements during image acquisition. An initial image
was captured to determine the perpendicular distance
from the greater trochanter to the inferior border of the
lateral epicondyle of the femur, which was defined as the
thigh length. Quadriceps cross-sectional area images
were acquired at 50% of the segment length in 0.8-cm
slices for 3 seconds. The pulse sequence was performed
with a view field between 400 and 420 mm, time
repetition of 350 ms, eco time from 9 to 11 ms, 2 signal
acquisitions, and matrix of reconstruction of 256 3256.
The images were transferred to a workstation (Advan-
tage Workstation 4.3; GE Healthcare, Milwaukee, WI,
USA) for QCSA determination. In short, the segment
slice was divided into the following components: skeletal
muscle, subcutaneous fat tissue, bone, and residual
tissue. (Figure 1) Finally, QCSA was assessed by computer-
ized planimetry by a blinded researcher (22). The CV for
QCSA assessments was 1.8%.
TABLE 2. Strength training regimens throughout 12 weeks.*
Groups
Wk. 1–4,
1st mesocycle
Wk. 5–8,
2nd mesocycle
Wk. 9–12,
3rd mesocycle Repetitions Rep per day
NP Monday Thursday Monday Thursday Monday Thursday
Back squat 3 38RM 3 38RM 3 38RM 3 38RM 3 38RM 3 38RM
Knee extension 2 38RM 2 38RM 2 38RM 2 38RM 2 38RM 2 38RM 960 40.0
TP Monday Thursday Monday Thursday Monday Thursday
Back squat 3 312RM 2 312RM 4 38RM 4 38RM 3 34RM 3 34RM
Knee extension 2 312RM 2 312RM 2 38RM 2 38RM 2 34RM 2 34RM 976 40.6
UP Monday Thursday Monday Thursday Monday Thursday
Back squat 3 312RM 4 36RM 3 310RM 4 36RM 2 38RM 4 34RM
Knee extension 3 312RM 3 36RM 2 310RM 2 36RM 2 38RM 2 34RM 976 40.6
*NP = Non-periodized; TP = traditional periodization; UP = undulating periodization.
Figure 1. Overview of the traced dominant leg quadriceps cross-sectional area at 3 different time points (pretest, 6, and 12 weeks).
Training Regimens Effects on Muscle Strength and Mass
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Strength Training Regimens. The participants underwent
a 12-week hypertrophy-oriented lower limb strength train-
ing regimen. Participants trained 2 days per week with
72 hours between training sessions. Strength training
intensity was 4–12 RM (to failure) for both back squat
(conventional Smith machine; Portico", Sa
˜o Paulo, Brazil)
and knee extension (pin-loaded weight machine; Portico",
Sa
˜o Paulo, Brazil) exercises. A 2-minute rest interval was
allowed between sets, whereas 3 minutes were respected
between exercises throughout the entire study. All exercises
were performed with constant speed (2-second eccentric
and 2-second concentric muscle actions) and a 908range
of motion at the knee joint. The mesocycles and ST regi-
mens adopted for each of the 3 experimental groups are
presented in Table 2.
Statistical Analyses
After normality (i.e., Shapiro-Wilk) and variance assur-
ance (i.e., Levene), a mixed model was performed for each
dependent variable (volume load, maximum strength, and
quadriceps CSA) assuming group (NP, TP, UP, and C)
and time (pre and post) as fixed factors and participants as
a random factor. Volume load was analyzed assuming
group (NP, TP, and UP) and time (first, second, and third
mesocycles) as fixed factors and participants as a random
factor (SAS 9.4; SAS Institute, Inc., Cary, NC, USA).
Whenever a significant F-value was obtained, a post hoc
test with a Tukey adjustment was performed for multiple
comparison purposes (25). In addition, mean difference
and 95% confidence intervals of the within-group absolute
difference (CI
diff
) were presented. Within-group effect
sizes (ES) were calculated as follows: mean post- minus
mean pre- divided by the pooled SD of pretest values. The
significance level was previously set at p#0.05. Results
are expressed as mean 6SD.
RESULTS
Volume Load and Training Compliance
No significant differences were observed in overall volume
load between training groups NP: 100,460.1 617 ,1 5 5 . 5 k g ,
TP: 95,642.5 616,340.6 kg, and UP: 102,780.1 618,119.9
kg (Figure 2A). When volume load was analyzed per
mesocycle, there was a significant main effect of time
(p#0.0001); all the experimental groups significantly
decreased volume at the third mesocycle when compared
with the first and second mesocycles (226.10%, 228.49%;
p#0.0003), respectively (Figure 2B). Training compliance
was 95.17% (i.e., 22.8 sessions).
Figure 2. Volume load. A- Total volume load, B-Volume load per mesocycle. *p#0.05 when compared with first mesocycle (main time effect). #p#0.05 when
compared with second mesocycle (main time effect).
TABLE 3. Back squat maximum dynamic strength (1RM, mean 6SD).*
Group (1RM kg) pre (1RM kg) 6-wk (1RM kg) 12-wk ES-pre-6-wk ES-6-wk-12-wk ES-pre-12-wk
Control 126.8 621.30 127.68 621.62 132.05 620.12 0.03 0.14 0.20
NP 140.76 623.9 164.87 631.2†170.95 636.85†0.95 0.19 1.19
TP 141.15 619.57 152.96 631.82†166.43 630.29†z0.45 0.38 0.99
UP 149.57 634.67 167.35 636.01†178.35 636.76†0.70 0.58 1.13
*ES = within-group effect size; NP = nonperiodized; TP = traditional periodization; UP = undulating periodization.
†p#0.05 when compared with pre (within-group comparisons).
zp#0.05 when compared with 6 weeks (within-group comparisons).
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Maximum Dynamic Strength
No significant between-group differences in maximum
dynamic strength were detected at pretest (p.0.05). There
was a significant group by time interaction (p#0.002) in
which squat 1RM values significantly increased in all train-
ing groups from pre to 6 weeks (NP: 17.0%—CI
diff
: mean 25.1
kg, 13.9–36.2 kg; TP: 7.7%—CI
diff
: mean 11.8 kg, 1.3–22.3 kg;
UP: 12.9%—CI
diff
: mean 17.7, 6.6–28.9 kg) and from pre to 12
weeks (NP: 19.5%—CI
diff
: mean 28.1 kg, 16.9–39.2 kg; TP:
17.9%—CI
diff
: mean 25.2 kg, 14.7–35.7 kg; UP: 20.4%—CI
diff
:
mean 28.7, 17.6–39.9 kg). In addition, TP was the only group
that significantly increased squat 1RM from 6 to 12 weeks
(9.4%—CI
diff
: mean 13.4 kg, 2.9–23.9 kg, p= 0.008). How-
ever, there was a strong trend towards significant increase at
the same period for UP group (6.9%—CI
diff
: mean 11.0,
20.141 to 22.1 kg, p= 0.053). There were no significant
differences from 6 to 12 weeks in NP group (1.5%—CI
diff
:
mean 2.9 kg, 28.1 to 14.1 kg, p#0.79). There were no
significant changes in RM for C group across time (p$
0.05) (Table 3).
Quadriceps Muscle Cross-Sectional Area
No significant between-group differences in QCSA were
detected at pretest (p.0.05). There was a group by time
interaction (p#0.0006). Quadriceps cross-sectional area
increased significantly in all training groups from pre to 6
weeks (NP: 5.1%—CI
diff
: mean 451.3 mm
2
, 159.1–743.4 mm
2;
TP: 4.6%—CI
diff
: mean 409.8 mm
2
, 134.4–685.2 mm
2
; UP:
5.3%—CI
diff
: mean 414.5 mm
2
, 122.4–706.6 mm
2
) and from
pre to 12 weeks (NP: 8.1%—CI
diff
: mean 715.0 mm
2
, 422.9–
1,007.0 mm
2
; TP: 11.3%—CI
diff
: mean 991.7 mm
2
,
716.2–1,267.0 mm
2
; UP: 8.7%—CI
diff
: mean 749.9 mm
2
,
457.7–1,042.0 mm
2
). In addition, only TP and UP signifi-
cantly increased QCSA from 6 to 12 weeks (TP: 6.4%—CI
diff
:
mean 581.9 mm
2
, 306.5–857.3 mm
2
; UP: 3.7%—CI
dif
: mean
335.4 mm
2
, 43.2–627.5 mm
2
,p#0.02). NP demonstrated
a weak trend toward significant increase in QCSA (2.8%—
CI
diff
: mean 263.8 mm
2
,228.3 to 555.9 mm
2
,p#0.084),
whereas there were no significant changes in C group for
QCSA across time (p$0.05) (Table 4).
DISCUSSION
The purpose of the current study was to investigate the
effects of different training regimens on muscle strength and
hypertrophy in recreationally active male college students.
Data support the hypothesis of similar ST-induced gains in
muscle strength and mass after 12 weeks of training between
experimental groups. Even though there were no significant
differences between training groups both at 6 and 12 weeks
of training, our within-group analyses suggest that after 6
weeks of an NP regimen, maximum strength improvements
were suboptimal when compared with periodized regimens.
In addition, periodized training programs seem to be more
effective than NP training programs at latter stages of
training, as only these groups presented significant increases
in muscle mass from the 6 to 12 weeks of training.
After 12 weeks of training, similar strength gains (;20%)
were observed between groups. Our data are in agreement
with previous literature demonstrating similar strength im-
provements following NP and periodized training models
in untrained individuals (2,16,24). Interestingly, despite
comparable end points, time course in strength gains was
different across groups. For instance, although not statisti-
cally significant, the NP group seemed to have the greatest
rate of change in 1RM after 6 weeks (17%) compared with
all the other groups (TP = 8%; UP = 12%) (Table 3). How-
ever, NP did not improve 1RM in the last 6 weeks of train-
ing (1.5%, p= 0.79). However, UP demonstrated a strong
trend (6.9%, p= 0.053) and TP significantly increased 1RM
(9.4%, p= 0.008) at the latter phase of the study. Although
it is attractive to suggest that periodized models may add
a benefit to strength gains, the specificity might, at least,
explain our results. For example, the TP was the group that
performed more training sessions at higher intensities dur-
ing the second part of the study (e.g., TP: 4 sessions at 8RM
and 8 sessions at 4RM), whereas UP group performed 2
sessions at 10RM, 2 sessions at 6RM, 4 sessions at 8RM,
and 4 sessions at 4RM. Therefore, TP and UP had more
sessions at higher intensities than NP group, which can
explain why the periodized groups demonstrated better
TABLE 4. Quadriceps muscle cross-sectional area (QCSA, mean 6SD).*
Group (QCSA mm
2
) pre (QCSA mm
2
) 6-wk (QCSA mm
2
) 12-wk ES-pre-6 wk ES-6-wk-12 wk ES-pre-12-wk
Control 8,913.3 61,041.9 8,751.0 61,136.3 9,149.1 61,264.2 20.15 0.34 0.21
NP 8,801.4 6983.8 9,247.1 6972.3†9,613.5 61,017.0†0.41 0.32 0.75
TP 8,689.4 6770.8 9,099.2 6892.7†9,681.1 61,049.4†z0.37 0.35 0.91
UP 8,407.2 61,449.0 9,064.0 61,503.2†9,399.3 61,538.6†z0.60 0.57 0.91
*QCSA = quadriceps cross-sectional area; ES = within-group effect size; NP = nonperiodized; TP = traditional periodization; UP =
undulating periodization.
†p#0.05 when compared with pre (within-group comparisons).
zp#0.05 when compared with 6 weeks (within-group comparisons).
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strength gains at the second half of the study. In addition,
a recent meta-analysis suggested that periodized models
have a small to moderate effect on 1RM compared with
NP models. Importantly, those authors reported that study
length was positively related to 1RM changes in periodized
models (28). In this regard, the second half of our study
partially agrees with the outcomes reported by this recent
meta-analysis, as ES from 6 to 12 weeks suggests a small
advantage for the periodized regimens (Table 3).
Furthermore, 1 benefit of periodization that has been
underrated for untrained individuals is that varying training
stimulus more frequently may enhance recovery and allow
subjects to manage fatigue properly. It is noteworthy men-
tioning that reduction in the overall number of repetitions at
the third mesocycle was only planned for the periodized
groups (i.e., TP and UP), whereas NP kept the total number of
repetitions constant. Despite a greater total number of
repetitions in the third mesocycle (i.e., NP: 320, TP: 160
and UP: 224), NP demonstrated similar reduced volume loads
when compared with TP and UP groups. Although interest-
ing, it is difficult to determine what produced an inability to
sustain volume load during the last mesocycle by the NP
group. One important characteristic of the current study was
that all sets were performed until failure. Although there is no
consensus on the efficacy of training to failure on strength
gains, some studies have suggested that fatigue and training to
failure may not be critical for strength gains in untrained
individuals (7,9). Therefore, our findings suggest that even for
untrained individuals, ST planning is important to reduce
fatigue and maximize strength gains over longer periods of
time.
Regarding muscular hypertrophy, the training groups
exhibited similar increases in QCSA after 12 weeks (e.g.,
NP: 8.1%, TP: 11.3%, and UP: 8.7%). To this point, only 1
study has investigated the short-term effects of periodized
and NP regimens on QCSA, which demonstrated similar
changes between the groups (22). Furthermore, the studies
that have compared the effects of TP and UP on muscle
hypertrophy parameters (i.e., CSA and muscle thickness)
reported no differences between the groups (13,16,21). In
fact, a recent meta-analysis comparing TP and UP demon-
strated that in matched volume load studies there is no evi-
dence supporting that 1 periodized regimen can produce
greater hypertrophic adaptations (10). In addition, a system-
atic review demonstrated an average increase in QCSA of
8.5% after different ST regimens (27). Therefore, from pretest
to 12 weeks, the magnitude of muscular hypertrophy re-
ported in the current study was similar between groups,
and it is in agreement with previous literature. Nonetheless,
the within-group ES from pretest to 12 weeks suggest a small
advantage for the magnitude of muscle hypertrophy of
the periodized groups when compared with NP regimen
(Table 4).
Yet , a s ob s e r v e d w it h t he s t r e n g t h da t a, d e sp i t e s im i la r
increases overall, muscle hypertrophic responses differed
between groups over time. Only periodized training regimens
significantly increased QCSA in the second half of the study
(i.e., from 6 to 12 weeks). However, it is important to mention
that the magnitude of muscle hypertrophy was similar across
the group from 6 to 12 weeks. In our study, the total number of
repetitions was very similar between groups before the
commencement of the experimental period, whereas there
were no differences in volume load. Our group has previously
demonstrated that after an 8-week ST period, reductions of
;54% in volume load were sufficient to sustain QCSA during
additional 8 weeks of reduced volume load training in
untrained individuals (24). In this respect, although volume load
was not significantly different between groups, the 2 groups
that reduced volume load the most during 7–12 weeks when
compared with 1–6 weeks (i.e., TP: 220.5% and UP: 218.7%
vs. NP: 27.3 % ) a n d trai n e d a t h i gher i n t e nsit i e s w ere th e o n l y
groups to show significant muscle hypertrophy in that period.
These outcomes suggest that even in untrained individuals, ST
planning may affect the time course of muscular adaptations.
Finally, although low-load schemes have been shown to be
efficient as heavy-load regimens inducing muscle hypertrophy
(19), our findings are in agreement with previous literature in
untrained individuals demonstrating that in volume load–
equated conditions, muscle hypertrophy might favor higher
training intensities (5,11,20).
Certainly, our study has inherent limitations. For
example, although the participants were strictly instructed
to maintain their normal diet, the lack of diet control
might be a confounding factor modulating muscle hyper-
trophy in different directions. Second, longer training
periods and more exercise variation would provide further
insight into the effects of training variability on muscle
adaptations. Finally and perhaps the most important is
that periodization is not a strict defined program. Rather,
it is a concept that encompasses different ways to
manipulate training variables. In this regard, a study
scrutinizing the effects of training regimens used in our
study on muscle hypertrophy while manipulating training
variables in a different fashion might report outcomes
different from the reported herein.
In conclusion, our results demonstrated similar ST-
induced adaptations after 12 weeks of either NP or
periodized training regimens. Importantly, NP training
stimulus seems to induce suboptimal muscular adaptations
at latter training stages (i.e.,aftertheinitial6weeks),
suggesting that, even for untrained individuals, ST planning
might be important to manage fatigue and optimize
training-induced adaptations.
PRACTICAL APPLICATIONS
Strength coaches and practitioners focusing on improving
muscular adaptations in untrained individuals should be
aware that early-phase (#6 weeks) organization of training
loads does not significantly affect strength or hypertrophy,
although NP may produce slightly greater strength gains
Journal of Strength and Conditioning Research
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VOLUME 32 | NUMBER 5 | MAY 2018 | 1243
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than the other groups. However, periodized ST models may
be advantageous at latter stages of training (after the initial 6
weeks), properly adjusting training stimuli and ultimately
optimizing muscular adaptations (i.e., strength performance
and hypertrophy) in untrained individuals.
ACKNOWLEDGMENTS
E.O. De Souza was supported by CNPq 152658/2011-5. C.
Ugrinowitsch is supported by CNPq 406609/2015-2, H.
Roschel is supported by CNPq307023/2014-1, and V. Tricoli
is supported by 310823/2013-7.
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Training Regimens Effects on Muscle Strength and Mass
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