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Impact of Range of Motion During Ecologically Valid Resistance Training Protocols on Muscle Size, Subcutaneous Fat, and Strength


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The impact of using different resistance training (RT) kinematics, which therefore alters RT mechanics, and their subsequent effect on adaptations remain largely unreported. The aim of this study was to identify differences to training at a longer (LR) compared with a shorter (SR) range of motion, as well as the time-course of any changes during detraining. Recreationally active participants in LR (aged 19 ± 2.6 years; n=8) and SR (aged 19 ± 3.4 years; n=8) groups undertook 8 weeks of RT and 4 weeks detraining. Muscle size, architecture, subcutaneous fat and strength were measured at weeks 0, 8, 10 and 12 (repeated measures). A control group (aged 23 ± 2.4 years; n=10) was also monitored during this period. Significant (p>0.05) post-training differences existed in strength (on average 4±2% vs. 18±2%), distal anatomical cross-sectional area (59±15% vs. 16±10%), fascicle length (23±5% vs. 10±2%) and subcutaneous fat (22±8% vs. 5±2%), with LR exhibiting greater adaptations than SR. Detraining resulted in significant (p>0.05) deteriorations in all muscle parameters measured in both groups, with the SR group experiencing a more rapid relative loss of post-exercise increases in strength than LR (p>0.05). Greater morphological and architectural RT adaptations in LR (owing to higher mechanical stress) result in a more significant increase in strength compared to SR. The practical implications for this body of work follow that LR should be observed in resistance training where increased muscle strength and size are the objective, since we demonstrate here that ROM should not be compromised for greater external loading.
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Institute for Performance Research, Department of Exercise & Sport Science, Manchester Metropolitan University, Crewe,
United Kingdom; and
Sports Institute Northern Ireland, University of Ulster, Newtownabbey, Belfast, Ireland
McMahon, GE, Morse, CI, Burden, A, Winwood, K, and
´, GL. Impact of range of motion during ecologically
valid resistance training protocols on muscle size, subcutane-
ous fat, and strength. J Strength Cond Res 28(1): 245–255,
2014—The impact of using different resistance training (RT)
kinematics, which therefore alters RT mechanics, and their sub-
sequent effect on adaptations remain largely unreported. The
aim of this study was to identify the differences to training at
a longer (LR) compared with a shorter (SR) range of motion
(ROM) and the time course of any changes during detraining.
Recreationally active participants in LR (aged 19 62.6 years;
n= 8) and SR (aged 19 63.4 years; n= 8) groups undertook
8 weeks of RT and 4 weeks of detraining. Muscle size, archi-
tecture, subcutaneous fat, and strength were measured at
weeks 0, 8, 10, and 12 (repeated measures). A control group
(aged 23 62.4 years; n= 10) was also monitored during this
period. Significant (p.0.05) posttraining differences existed
in strength (on average 4 62 vs. 18 62%), distal anatomical
cross-sectional area (59 615 vs. 16 610%), fascicle length
(23 65 vs. 10 62%), and subcutaneous fat (22 68 vs. 5 6
2%), with LR exhibiting greater adaptations than SR. Detrain-
ing resulted in significant (p.0.05) deteriorations in all muscle
parameters measured in both groups, with the SR group expe-
riencing a more rapid relative loss of postexercise increases in
strength than that experienced by the LR group (p.0.05).
Greater morphological and architectural RT adaptations in the
LR (owing to higher mechanical stress) result in a more signif-
icant increase in strength compared with that of the SR. The
practical implications for this body of work follow that LR
should be observed in RT where increased muscle strength
and size are the objective, because we demonstrate here that
ROM should not be compromised for greater external loading.
KEY WORDS detraining, hypertrophy, muscle architecture,
range of motion, stress, strength training
To the strength and conditioning practitioner, the
design of a resistance training (RT) program will
incorporate a selection of exercises that will ideally
reflect both functional tasks of a chosen sport and
also the ability of the exercise to bring about a desired set of
adaptations to enhance function and ideally, therefore, phys-
ical performance. Because muscle force is proportional to
muscle cross-sectional area (29), is intimately linked with
power, and is a key determinant to success in many sports,
muscular hypertrophy is often a key outcome after RT. The
degree of hypertrophy arises from the manipulation of the
training stimulus: exercise selection and order, mode of con-
traction, intensity, recovery, and volume (38). Although
studies on several of these variables are numerous, effects
of training kinematics on training mechanics remain largely
unreported. Taking the squat exercise (which is an exercise
often used to overload the knee extensor muscle group dur-
ing a hypertrophic training phase) as an example, studies
have investigated the relationship between range of motion
(ROM) of the squat and its effects on thigh muscle activation
and joint moments (51), tibiofemoral shear and compressive
forces (36), and on peak velocity and force (10). One poten-
tial important aspect of training kinematics (i.e., ROM) that
practitioners may not have previously taken into consider-
ation is the effects of ROM on muscle mechanics during RT,
and the subsequent adaptations as a result. Suboptimal or
inadequate loading of the muscle group therefore could lead
to the goals of the RT program not being met.
As muscle length changes during force production to
bring about movement, the moment arm of the series elastic
component (i.e., the tendon) also changes. Therefore, the
internal tension a muscle experiences at different joint angles
will change despite there being no alterations in external
Address correspondence to Gladys Onambe
´-Pearson, g.pearson@
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VOLUME 28 | NUMBER 1 | JANUARY 2014 | 245
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absolute load. Simultaneous to the change in moment arm is
the effect of changing muscle length on actin-myosin
interactions and thus crossbridge states (18). A changing
muscle length will vary both these cellular factors, thus im-
pacting on the force-length relationship in the muscle (37).
The magnitude of mechanical stress is known to induce
muscle hypertrophy (30); therefore, increased mechanical
stress at 1 joint angle compared with another could act as
a signal for additional sarcomerogenesis at that muscle
length based on the differential stress imposed through the
moment arm changes. To further augment sarcomerogenesis
at different muscle lengths are the effects stretch has on
muscle. Muscles undergoing different amounts of stretching
and shortening have been shown to adapt to their new func-
tional lengths by the addition or removal of sarcomeres in
series (12,46,50), with an increase in functional length asso-
ciated with increased protein synthesis (13).
This identifies “average muscle length-specific training” as
a potential modulator of the training-induced hypertrophic
response. Only 1 previous study to our knowledge (26) has
investigated training at different joint angles on muscle size
and function in vivo, but the results do not reflect what the
theory would have predicted. Nine men completed a 12-
week unilateral isometric training program (70% maximum
voluntary contraction 315 seconds 36 sets) on the knee
extensors at either a short (508of knee flexion) or a long
(1008) muscle length. The authors found that whole quadri-
ceps volume increased significantly in both short (+10 6
1%) and long (+11 62%) muscle lengths, although there
was no significant difference between the groups. However,
it should be noted that the isometric-only protocol adopted
by Kubo et al. (25) may not reflect the practices of individ-
uals training to optimize gains in strength and hypertrophy
in addition to the limited transfer of the functional aspect of
an isometric exercise.
Architectural adaptations have also been shown to occur
with RT. Alterations to the fascicle angle of pennation impacts
on the physiological cross-sectional area (CSA) and therefore
force-generating capacity (1) of muscle, whereas changes to
fascicle length are associated with alterations to the force-
velocity relationship (48), which therefore impacts potential
power output. Regarding fascicle angle, there appears to be
a strong relationship between increases in muscle size and
increases in pennation angle (4,19,20). Although an increase
in pennation angle is expected to allow an increase muscle
force (up to an upper limit of 458), at greater pennation angles,
the effective contractile force exerted on the aponeurosis is
reduced to a greater extent, off-setting the increase in force
production from the increased number of actomyosin cross-
bridges activated in parallel (35,42). Hence, it is important to
monitor both fascicle angle and functional changes in strength
in the muscle of interest. To systematically determine what
changes are evident in the muscle in terms of hypertrophic
and architectural changes is therefore key to optimizing train-
ing protocols with the associated training adaptations.
It is also important to describe how the muscle responds
to a reduction in loading. Detraining is the partial or
complete loss of training-induced adaptations, in response
to an insufficient loading stimulus (32). Significant decre-
ments in strength, electromyography (EMG), and mean
fiber CSA have been reported in as little as 2 weeks of de-
training (16), with similar observations in chronic detraining
periods ($4 weeks) alluding to either losses in mass, strength
or neural activation, or combinations of these factors
(15,25,34). Also, most studies have tended to report changes
after detraining after similar time courses to the preceding
RT, that is, between 3 and 6 months. If there appears to be
a greater hypertrophic response at 1 muscle length over
another, it would also be of interest to determine whether
there is a differential modulation of detraining-induced mal-
adaptations after greater initial gains from RT at different
muscle lengths. Thus, if these greater gains are still evident
after detraining, it would further highlight the value of using
more optimal training mechanics within an RT program.
The purpose of this study was to therefore describe the
changes to vastus lateralis (VL) anatomical CSA (aCSA),
architecture, subcutaneous fat content, and strength after 8
weeks of dynamic resistance exercise at 508compared with 908
of knee flexion, using an ecologically valid training regime. In
brief, the specified angle is the position at which the training
load is held isometrically for 2 seconds. With 508, this involves
thus a shorter “average muscle length,” whereas with 908,this
involves a longer ROM (LR) in the dynamic phase of the
exercise and thus a longer “average muscle length.” A second
objective was to describe the effects of the detraining time
course over 4 weeks on the aforementioned variables. It was
hypothesized that the group training at longer muscle length
(908joint angle) would undergo a greater amount of skeletal
muscle hypertrophy because of increased physiological stress
and stretch on sarcomeres compared with the group training at
508. It was also expected that the LR group would continue to
have a large muscle mass after detraining, because of greater
initial gains. Strength-related parameters were expected to fol-
low the same pattern as those associated with hypertrophy.
Experimental Approach to the Problem
We sought to compare changes in muscle size, architecture,
function, and subcutaneous fat after 8 weeks of RT and 4
weeks of detraining covering 2 distinctly different ROMs
(the between-subjects independent variable) to identify the
most effective method of RT based on the adaptations
observed (dependent variables described below). The par-
ticipants performed isoinertial RT at either a shorter average
muscle length (ROM 0–508knee flexion) or a longer average
muscle length (ROM 0–908knee flexion) 3 times per week at
80% 1RM during the training period and performed habitual
activity during detraining. Dependent variables were
Range-of-Motion Specific Muscle Loading
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measured at baseline, posttraining, after 2 weeks of detrain-
ing and again after a further 2 weeks of detraining (the
within-subject independent variable). Testing was completed
within 3 hours of the time of day at weeks 0, 8, 10, and 12
to minimize any impact of diurnal variability in muscle func-
tion (28). The participants were allowed to drink water ad
libitum during testing and training sessions.
Twenty-six volunteers (14 men and 12 women; age range of
18 to 26 years old) from the local university campus gave
written informed consent to participate in this study with all
procedures and experimental protocols approved by the local
Ethics Committee within the Department of Exercise and
Sport Science. Exclusion criteria included the presence of any
known musculoskeletal, neurological, and inflammatory and
metabolic disorders or injury. The participants took part in
recreational activities such as team sports and had either never
taken part in lower limb RT or over the last 12 months.
Sixteen activity-matched men and women were randomly
assigned to either the SR (n= 8–4 men, 4 women) training
group or to the long ROM (LR; n= 8–4 men, 4 women)
training group. Ten participants (6 men and 4 women) were
assigned to the nontraining control group (Con) to monitor
for random variation in the muscle parameters investigated in
this population over the training and detraining periods. The
physical characteristics of the study population are outlined in
Table 1. A 1-way analysis of variance (ANOVA) revealed that
the population was homogeneous at baseline for all parame-
ters of interest and in physical characteristics (p.0.05). As
body mass and external load provide the total training stim-
ulus in a number of the leg exercises adopted in the training
program (2 out of the 6), it should be noted that the partic-
ipant groups showed no difference in body mass at baseline,
week 8, 10, or 12. Furthermore, it was felt that training at
loads relative to 1RM provided greater external validity to
the practices of individuals undertaking RT.
Resistance Training Program. Resistance training was per-
formed 3 times per week (twice supervised and 1 home-
based session) by both the SR and LR training groups for 8
weeks, using a combination of free, machine (Pulse Fitness,
Congleton, United Kingdom) and body weights. A general-
ized warm-up was completed at 70–75% age-predicted max-
imum heart rate on a treadmill for 5 minutes, after which
a goniometer was attached to the center of rotation of the
knee. As the subject performed each exercise (Table 2), the
goniometer rotated from 08(full extension), and a training
partner confirmed from the scale when the participant had
reached 50 or 908of knee flexion during the eccentric phase
and therefore could hold the load steady over 2 seconds,
before beginning the concentric phase of movement. Move-
ment speed was dictated by a 1-second metronome. All ex-
ercises involved eccentric and concentric loading, except for
the Sampson chair, which was isometric loading. The subjects
completed 2 familiarization sessions at 70% of 1RM before
commencing the RT program. Exercises were performed at
80% of the 1RM as determined at the training angle, for
example, the SR group 1RM was the greatest weight lifted
whilst performing at 508knee flexion. The 1RMs were mea-
sured every 2 weeks, and the training loads were adjusted
accordingly. Manipulation of the exercise variables (exercise
selection and order, repetitions, sets, recovery, and intensity
shown in Table 2) were all chosen based on empirical evi-
dence presented in the American College of Sports Medicine’s
Progression Models for RT for Healthy Adults for increasing
muscle hypertrophy (38).
Muscle Architecture and Subcutaneous Fat. Architecture was
measured at rest with each participant seated in an upright
position on an isokinetic dynamometer (Cybex, Phoenix
Healthcare Products, Nottingham, United Kingdom). After
calibration, each participant was positioned with a hip angle
of 808(straight back 908) and knee at 908knee flexion
(straight leg 08). All muscle architectural measurements were
determined using real-time ultrasonography (AU5, Esaote
Biomedica, Genoa, Italy) at rest, with images captured at
25 Hz using a digital video recorder (Tevion, Medion Aus-
tralia Pty Ltd, St Leonards, Australia). Vastus Lateralis fasci-
cle pennation angle (u) was measured as the angle of fascicle
insertion into the deep aponeurosis (42). Images were ob-
tained perpendicular to the dermal surface of the VL and
oriented along the midsagittal plane of the muscle. Images
were taken at 25, 50, and 75% of the total femur length (as
described below) and 50% of muscle width at each point
(where 50% muscle width is defined as the midpoint
between the fascia separating the VL and rectus femoris,
and fascia separating the VL and biceps femoris muscles).
Fascicle length was defined as the length of the fascicular
path between the deep aponeurosis and superficial aponeu-
rosis of the VL. The majority of fascicles extended off the
acquired image, where the missing portion was estimated by
linear extrapolation. This was achieved by measuring the
linear distance from the identifiable end of a fascicle to the
intersection of a line drawn from the fascicle and a line
drawn from the superficial aponeurosis. This method has
TABLE 1. Participants’ physical characteristics at
Group Age (y) Mass (kg) Height (cm)
SR 19 63.4 74.9 610.1 174 613.3
LR 19 62.6 73.8 614.9 171 611.8
Con 23 62.4 77.9 613.1 176 69.5
*SR = shorter range of motion; LR = longer range of
motion; Con = control group.
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been shown to produce reliable results previously (4). All
images were analyzed and measured using Image J (Wayne
Rasband, National Institutes of Health, Bethesda, MD, USA).
Subcutaneous fat was estimated using the same images as
taken for muscle architecture. After calibration in Image J to
coincide with the scale of the ultrasound image, a line from
the top to the bottom of the layer of fat visualized was drawn
at 3 regular intervals on the ultrasound image. The average
lengths of these 3 lines were taken to estimate the average
thickness of the subcutaneous fat layer in millimeters. Care
was taken not to deform or compress the subcutaneous fat
with minimal pressure applied to the dermal surface with the
ultrasound probe.
Muscle Force Modeling. Because of the changing moment arm
length of the patella tendon at discrete knee joint angles,
differences in muscle force produced between the groups
had to be accounted for. Thus, quadriceps forces at the
patella tendon were calculated as follows:
QuadForce ¼QuadMaxTorque þHamCoTorque
Moment ArmPT ;
HamCoTorque ¼Co ConEMG 3FlexMaxTorque
where Co-Con
is co-contraction of the antagonist muscle
(biceps femoris), and Max BF
is the maximum antagonist
EMG. The Flex
maximum flexion torque and
Moment Arm
being the
moment arm of the patellar
tendon (values obtained from
dual energy x-ray absorptiom-
etry scans).
Muscle Anatomical Cross-Sec-
tional Area. The VL muscle
aCSA was measured using
real-time ultrasonography at
rest. The aCSA was measured
at 3 sites—25, 50, and 75% of
the total femur length. Femur
length was defined as the line
passing from the greater tro-
chanter to the central palpable
point of the space between the
femur and tibia heads when
Echo-absorptive tape was
placed at regular intervals
(;3 cm) along the muscle width at each site so that when
the probe was placed on the leg, 2 distinct shadows were
cast on the ultrasound image. Therefore, each ultrasound
image provided a section of VL within the boundaries set
by the 2 shadows and fascia surrounding the muscle. Each
of these sections was analyzed for the total area using
Image J to provide a total aCSA at that particular site. This
method has been validated previously (40).
Strength Measurement. Maximal isometric knee extension
torque was measured with the knee at a range of angles,
that is, 30, 50, 60, 65, 70, 75, and 908(full knee extension =
08) on the right leg of all the participants. The order of
testing by knee angle was randomized so as to minimize
any systematic fatigue effect. After a series of warm-up trials
consisting of 10 isokinetic contractions at 608$s
at 50–85%
maximal effort, the participants were instructed to rapidly
exert maximal isometric force against the dynamometer
(Cybex NORM, Medway, MA, USA) lever arm. The partic-
ipants were given both verbal and visual encouragement and
feedback throughout their effort. Joint torque data were dis-
played on the screen of a Mac Book Air computer (Apple
Computer, Cupertino, CA, USA), which was interfaced with
an A/D system (Acknowledge, Biopac Systems, Santa
Barbara, CA, USA) with a sampling frequency of 200 Hz.
Isometric contractions were held for approximately 2 sec-
onds at the plateau with a 60-second rest period between
contractions. Peak torque was expressed as the average of
data points over a 200-millisecond period at the plateau
phase (i.e. 100 milliseconds either side of the instantaneous
peak torque). The peak torque of 3 extensions was used as
the measure of strength in each participant.
TABLE 2. Resistance training program outline.*
Exercise Reps Sets Recovery (s) Intensity (1RM %)
Day 1
BB back squat 10 3 90 80
Knee extension 10 3 60 80
Bulgarian split squat 10 3 90 80
DL Sampson chair 4 310-s holds 3 60 -
Day 2
BB back squat 10 3 90 80
Knee extension 10 3 60 80
Leg press 10 3 90 80
DB lunges 10 3 60 80
Day 3
BW squats 30 3 90 -
DL Sampson chair 4 320-s holds 3 60 -
BW lunges 30 3 90 -
SR Sampson chair 5 35-s holds 3 60 -
*BB = barbell; DB = dumbbell; DL = double-legged; SR = single-legged; BW = body
weight; RM = repetition maximum.
Exercises were carried out at 80% 1RM where appropriate or using body mass.
Range-of-Motion Specific Muscle Loading
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Statistical Analyses
Data were parametric and were therefore analyzed using
a mixed-design repeated measures ANOVA. The within
factor was the phase of training (i.e., weeks 0, 8, 10, and 12)
and the between factor was training group (i.e., SR, LR, or
Con). Post Hoc contrast analyses with Bonferroni correc-
tions were used to compare data to baseline (“within” factor)
and to control group (“between” factor). All data are pre-
sented as mean 6SEM. Statistical significance was set with
alpha at #0.05. In terms of the sample size in this study, the
average statistical power of the measured muscle parameters
(CSA, pennation angle, fascicle length, and strength) was
statistically adequate at beta = 0.86.
Repeatability of the Measurements. A small pilot study was
conducted at the onset of the study on a similar population
(i.e., age and physical characteristics). Repeated measures of
VL muscle anatomical CSA, architecture, and strength on
a group of 5 individuals (2 men, 3 women) were collected on
3 separate occasions. Within-day coefficients of variation
(CVs in percent) of 1.5, 1.9, 1.3, 2.6, and 0.8%, and between-
day CVs of 2.6, 2.1, 1.6, 2.9, and 1.8% were yielded for
aCSA, fascicle length, fascicle pennation angle subcutane-
ous fat, and strength, respectively. Therefore, the repeat-
ability of the measurements was within an acceptable range
of error (3).
Total Training Load
To allow internal force comparisons, external training
loads were monitored in each group. Total average loads
(mean 6SD) lifted for externally loaded (i.e., not just using
body mass) exercises completed were (a) Squat: SR 99 6
10 kg, LR 80 68 kg; (b) Leg Press: SR 60 619 kg, LR 48 6
17 kg; (c) Leg extension: SR 51 617 kg, LR 46 615 kg. To
accurately assess internal muscle forces produced, the
change in resistance moment arms of the CAM pulley
machine used during leg extensions were also measured.
Based on the training load for the leg extension exercise
stated above for each group, the resistance machine load
component yielded on average a 7% increase in external
torque produced in the SR group compared with LR (SR:
137 vs. LR: 128 N$m).
The results in the subsequent sections describe paired
physiological changes relative to baseline.
Muscle Anatomical Cross-Sectional Area at 25, 50, 75%
Femur Length
The results at all femur lengths are presented in Table 3. The
VL CSA increased significantly (p,0.05) relative to baseline
after training at all sites in both training groups. The signif-
icant training effect remained during the whole detraining
period in both training groups at both 50 and 75% but was
TABLE 3. Paired changes to VL CSA and pennation angle of fascicles at different femur lengths over the training and
detraining phases.*
Site (% femur length) Baseline Week 8 Week 10 Week 12
25 CSA SR 2,877 6338 SR 3,425 6303zSR 3,361 6306zSR 3,265 6310
LR 2,684 6427 LR 3,592 6303zLR 3,461 6309zLR 3,328 6295
Con 3,201 6253 Con 3,086 6259 Con 3,079 6240 Con 3,086 6259
50 CSA SR 3,033 6289 SR 3,699 6342zSR 3,526 6334zSR 3,382 6304z
LR 3,004 6385 LR 3,545 6339zLR 3,424 6349zLR 3,233 6338z
Con 3,326 6354 Con 3,314 6364 Con 3,294 6357 Con 3,314 6364
75 CSA SR 1,081 6175 SR 1,162 6127zSR 1,115 6127zSR 1,037 6119z
LR 1,074 6224 LR 1,505 6217z§ LR 1,369 6200zLR 1,219 6191z
Con 1,366 6165 Con 1,370 6185 Con 1,358 6175 Con 1,370 6185
25 PEN SR 10.1 60.3 SR 10.3 60.3zSR 10.0 60.7 SR 9.9 60.2
LR 10.2 60.3 LR 11.2 60.6zLR 11.1 60.6 LR 11.0 60.6
Con 11.9 60.2 Con 12.2 60.1 Con 12.0 60.1 Con 12.2 60.1
50 PEN SR 16.5 60.5 SR 17.2 60.3zSR 16.8 60.9 SR 16.4 60.4
LR 15.9 60.2 LR 17.1 60.8zLR 16.6 60.8 LR 16.0 60.6
Con 16.4 60.8 Con 16.4 60.7 Con 16.3 60.7 Con 16.4 60.7
75 PEN SR 16.0 61.4 SR 17.9 61.2zSR 16.8 60.9zSR 16.8 60.9
LR 15.5 60.6 LR 17.5 60.7zLR 17.2 60.6zLR 16.3 60.5
Con 19.4 60.7 Con 18.5 60.7 Con 18.4 60.6 Con 18.5 60.7
*CSA = cross-sectional area; PEN = pennation; SR = shorter range of motion; LR = longer range of motion.
Values are millimeters squared and degrees (mean 6SE).
zSignificantly different from other training group.
§Significantly above baseline.
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not evident at 25% of femur length after week 10. There was
a trend for LR to exhibit greater relative gains in aCSA
compared with SR at all sites, which was significant at week
8 at 75% of femur length. It was found that there was not
only a main training effect (p,0.05) but also a main group
effect after week 8 (p,0.05) with LR exhibiting a 59 615%
compared with SR showing 16 610% increment in VL
aCSA. Surprisingly, after the first 2 weeks of detraining,
the group effect was no longer
evident (p= 0.07) although
both training groups were still
significantly above baseline
at weeks 10 and 12. There
was no notable change over
the 12-week period for the
Muscle Architecture
Fascicle Pennation Angle—25, 50,
75% Femur Length. Table 3
shows the changes in fascicle
pennation angle at each site
for all 3 groups. At 25%, there
was a main effect of training
(p,0.05) for each group, with
no significant effect of group.
Pennation angles recorded at
baseline increased by 2 65
and 9 66% at week 8 for the
SR and LR groups, respec-
tively. However, by weeks 10
and 12, the effect of training
was negated with values return-
ing toward baseline (p.0.05).
This pattern was repeated at
50% of femur length with the
main effect of training (5 6
3% SR, 9 63% LR) reverted
after 2 weeks without the train-
ing stimulus. This was again the
case for pennation angles at
75%; however, the significant
increase because of the RT
was observed until week 10
but had receded toward base-
line after the 4 weeks of de-
training at week 12.
Fascicle Length—25, 50, 75%
Femur Length. There was a sig-
nificant main effect of RT on
fascicle length at all 3 sites
(Figure 1, p,0.05), which re-
mained significantly elevated
above baseline values after the
detraining period, with both
training groups significantly
increasing (p,0.05) fascicle
length at all sites at weeks 8,
Figure 1. Graph showing relative changes in fascicle length (millimeters) during training and detraining. A)
Changes at 25%, B) at 50%, and C) at 75%. *Significant relative change above baseline in both groups.
#Significantly different from the other training group. Significantly different (p,0.05) from the control group
(mean 6SE).
Range-of-Motion Specific Muscle Loading
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10, and 12 compared with controls. Although there was no
group effect at 25%, a significant group effect (p,0.05) did
occur at both 50 and 75% of the femur length. The
LR fascicle lengths increased 23 65, 19 64, 16 64% at
weeks 8, 10, and 12 from baseline in contrast to the SR
group’s less pronounced increments of 10 62, 6 62, and
262% during the same time period. All the values were
significantly enhanced compared with baseline in both
groups except for SR at week 12. At 75%, there was a similar
significant (p,0.05) group effect with relative increases of 19
63, 13 63, and 10 62% at weeks 8, 10, and 12 for LR from
baseline compared with 11 62, 5 64, and 2 62% for SR
during the same period.
Subcutaneous Fat 25, 50, 75 Femur Length. The training
intervention resulted in appreciable reductions in fat in both
SR and LR training groups between weeks 0 and 8 (p,
0.05) at all measured sites. At 25%, the SR group reduced
fat levels from 16.2 63.9 to 15.6 63.8 mm (2461%),
compared with LR (18.1 64.0 to 15.4 63.3 mm [214 6
3%]) posttraining; however, no group effect existed. After
training ceased, both groups remained significantly lower
than baseline at week 10 (2362% SL and 2963%
LR), but by week 12, there was no main effect of training
and detraining on either group (p.0.05), although there
was a strong trend for a group effect at this time point (p=
0.057). The control group did not fluctuate significantly from
baseline values during weeks 8, 10, and 12. There was also
considerable subcutaneous fat loss at 50% after RT, with
greater losses achieved by the LR group. Both lost 6.8 6
1.2 mm after training; however, LR produced a loss of 22 6
8% compared with SL with a 5 62% loss at this phase of the
protocol. The main effect of group remained during weeks
10 and 12, as SR regressed toward baseline by week 12,
whereas LR still possessed significant losses at this phase
(210 66%). There was a similar trend seen at 75% where
a main effect of both group and training existed at week 8
(p,0.05). This difference was
not present at week 10 or 12
although both training groups
had significantly less fat (p,
0.05) compared with that at
baseline during the detraining
period (7 63% SL and 9 6
1% LR).
Muscle Strength. There was
a main effect of training on
the MVCs of both training
groups (p.0.05) at each of
the training end ROMs, with
SR recording an increase of 5
610% at 58and 30 65% for
LR at 908. There were no dif-
ferences (p.0.05) between
absolute MVC in SR and LR at baseline or after training.
In agreement with previous observations after isometric
joint-angle specific training, there was evidence of angular
specificity of training in both the groups with SR signifi-
cantly (p.0.05) increasing MVCs at 50, 60, 65, and 708(i.
e., those closest to the training angle—Table 4), whereas LR
increased MVCs over the entire angular range, that is, 30–
908. The angle of peak torque altered from 75 to 708at week
8 in SR, where it remained for the duration of detraining in
weeks 10 and 12. In LR, the angle of peak torque was orig-
inally 708and did not change after training and detraining.
By week 10, both groups displayed an average 6 62%
strength reduction (relative to the posttraining strength val-
ues), with SR not significantly above baseline (0 62%) in
contrast to LR remaining significantly above both baseline (p
,0.05) and SR (p= 0.027) at weeks 10 and 12. The control
group’s strength did not significantly alter during the 12-week
training and detraining period (p.0.05).
The current investigation aimed to study the in vivo effect of
resistance exercise training and detraining over a larger ROM
and hence longer average muscle length (0–908knee flexion—
LR) vs. a smaller ROM and hence shorter average muscle
length (0–508knee flexion—SR) on morphological, architec-
tural, and functional changes in the VL. It was hypothesized
that the group training over a wider range of joint angles (LR)
would undergo a greater amount of skeletal muscle hypertro-
phy because of increased physiological stress and stretch on
sarcomeres compared with the group training over a shorter
range of joint angles (SR). It was also hypothesized that the
LR group would still have a greater muscle mass after detrain-
ing, probably because of greater initial gains. Our findings
partly support these hypotheses in that although there were
no notable changes to any of the muscle parameters in the
control group during a 12-week nontraining period, significant
adaptations were observed in both SR and LR training groups
TABLE 4. Changes in quadriceps MVC over a range of knee flexion angles from
baseline to week 8 (posttraining).
Knee flexion angle (8)
Torque (N$m) baseline—week 8 Relative change (%)
30 106–108 102–127 2 681865*
50 167–175 157–193 5 610* 16 64*
60 191–197 186–213 4 65* 11 67*
65 207–216 194–231 5 64* 19 68*
70 212–225 202–247 6 62* 13 62*
75 218–215 193–232 216318611*
90 216–218 161–208 1 623065*
*Significantly above baseline measures.
Journal of Strength and Conditioning Research
VOLUME 28 | NUMBER 1 | JANUARY 2014 | 251
Copyright © National Strength and Conditioning Association Unauthorized reproduction of this article is prohibited.
across all the muscle measurements. What is more, there was
a significant main effect of training where strength, VL fascicle
length, VL aCSA increased, whereas midthigh subcutaneous
fat decreased to a greater extent after training at a longer
muscle length compared with a shorter muscle length.
Further, as per our expectation of greater physical demands
of 1 training setup over the other, the stresses experienced by
the knee extensors, although comparable in terms of an eco-
logically valid training program setting and in terms of abso-
lute loads lifted were 10–25% greater in SR, in fact translated
to approximately 32% greater internal stresses in the group
training over the LR. This has a major impact on how both
coach and athlete should view the impact of ROM on mus-
cular adaptations. It is often tempting for an athlete to reduce
joint ROM to accommodate a larger external load in the belief
that lifting heavier will confer an advantage in adaptation.
However, from the evidence presented, without an apprecia-
tion of internal muscle mechanics, this assumption would be
The relative increases in VL size after 8 weeks of RT
reported in this study (21 68% in SR and 44 613% in LR—
averaged across the 3 sites) are much greater than those
previously reported in a similar study (26). It should be how-
ever noted that this study (26) is the only other known study
to our knowledge reporting changes specifically in VL size
after training at shorter vs. longer muscle length (;11 67%
ST and ;13 612% LT—values estimated from Figure 2 in
their Results section). The discrepancy between the 2 sets of
results would not only arise from the differences between
measurements of VL size (volume vs. aCSA) but also from
the difference in training protocols (isometric vs. combined
isoinertial and isometric) between Kubo et al. (26) and this
study. Indeed metabolic cost and work done are greater
during dynamic (i.e., concentric and eccentric) compared
with isometric contractions (49). Therefore, a greater
work-induced hypertrophic effect of the combined training
may have produced the variation in hypertrophy gain differ-
ences between the 2 studies (11). Previous research on
RT-induced whole quadriceps aCSA showed changes of
18.8 67.2, 13.0 67.2, and 19.3 66.7 at distal, central, and
proximal sites, respectively (34). It is nonetheless difficult to
compare the studies directly, however, not only owing to the
fact this study measured aCSA of the VL as opposed to all
4 quadriceps muscles but also the earlier report (34) showed
a significant difference in hypertrophic response between the
components of the quadriceps muscle group. In a review of
hormonal responses and adaptations to exercise (24), the
authors suggest exercises involving large muscle masses are
superior to more isolated exercises to elicit greater hormonal
responses. Therefore, the large mass exercises such as the
bilateral squat in our study would elicit a greater hormonal
response to that of a seated unilateral knee extension on a
dynamometer as in the study of Kubo et al. (26).
Kubo et al. (26) estimated that internal VL force during
isometric MVC at 1008of knee flexion was 2.3 times greater
than that at 508. This is key because mechanical stress mag-
nitude is known to induce muscle hypertrophy (30). Using
the 1RM training loads, patellar tendon moment arm and
aCSA, it was found that the mean force per unit area of
muscle was 5.1 N$mm
in the SL group compared with
6.8 N$mm
in the LR group. The results of this study
showed a nonsignificant trend for the LR group to exhibit
a greater VL aCSA after RT compared with SR at each site.
Importantly, in support of these beneficial morphological
adaptations in the LR group, this group had a significantly
greater increase in strength than SR group after training at
all knee angles measured, which has previously been dem-
onstrated after isometric training (26). In addition, Campos
et al. (6) found that the subjects who trained with higher
loads (i.e., 3–5 reps and therefore experiencing greater force)
increased maximal strength more significantly than moder-
ate (9–11 reps) or low (20–28 reps) loads, whereas the low to
moderate repetition groups experienced the greatest hyper-
trophic gains in the 3 major fiber types (12.5–26%) after
8 weeks of RT. The above, in addition to previous work from
Staron et al., shows that the hypertrophic training response
is accompanied with a gradual transition in the percentage of
fiber type and myosin heavy chain isoform (6,45), which
may explain the disassociation between muscle strength
and muscle size increments.
The magnitude of hypertrophy at 75% of the femur length
was greater for LR after training. Relative increases were
59 615% for LR and 16 610% for SR, displaying evidence
for region-specific hypertrophy. This has been observed pre-
viously after knee extensor RT (33,34,43). With both force
generation and stretch being effective stimuli for muscle
growth (14), the discrepancies in CSA between the groups
may be because of regional differences in the total stimulus
transmitted along the length of the muscle. Evidence exists
that there is relatively high serial and parallel distribution of
muscle fiber strain during transmission of myofascial force
(17). Thus, the LR group could have experienced a greater
strain at a more distal portion of the VL, which was also
transmitted laterally, resulting in a greater stimulus and
therefore enhanced hypertrophy at this site. Because muscle
force is proportional to CSA, this provides a basis for
enhancing the force output of the muscle, which is reflected
in our strength results.
A major finding of this study was the greater increase in
fascicle length at all sites in the LR group compared with SR
group, although only significantly so at 50 and 75% of total
femur length. In vivo increases in fascicle length are
associated with the addition of sarcomeres in series (assum-
ing a fixed sarcomere length) and appear to be strongly
influenced by muscle length or stretch (12,46,50). A study by
Boakes et al. (5) wherein surgery placed the thigh muscles
under constant stretch to address a leg-length discrepancy,
resulted in a 4-cm femoral lengthening. Fascicle and sarco-
mere length was measured in VL postoperatively and after
12 months. The results showed that in vivo fascicle length
Range-of-Motion Specific Muscle Loading
Journal of Strength and Conditioning Research
Copyright © National Strength and Conditioning Association Unauthorized reproduction of this article is prohibited.
increased and sarcomere length decreased, with sarcomero-
genesis from approximately 25,000 to 58,650 as a result of
adaptation to stretch. In this study, our protocol increased
the muscle excursion range of the quadriceps to a greater
extent in the LR group compared with that in the SR group.
The results from this investigation support pervious animal
research evidence (22) that “average muscle length” (or excur-
sion range) is a possible primary stimulus for increases in
fascicle length in adult skeletal muscle. As mentioned previ-
ously, changes in fascicle length produce alterations to the
force-velocity relationship in muscle (48) and could therefore
impact on an athlete’s potential for power production.
Further architectural adaptations included a significant
increase of pennation angle (Pu) in both training groups
(Table 3). A functional consequence of an increase in Puis
that more contractile material can be packed in parallel for
a given anatomical cross-section (19,42). The Puhas been
shown to increase after resistance exercise (1,4,20,39,43)
and is usually closely associated with an increase in ana-
tomical CSA in the quadriceps (42). Despite not reaching
between-group significance, the average increase in Pu
across the 3 sites was greater for LR than for SR (11 65
vs. 7 64%, respectively). Thus, this could also have been
a factor in contributing to the LR group’s greater strength
after training.
A further benefit experienced by the LR group was
a greater reduction in subcutaneous fat at 50 and 75% of
the femur length. In the athletic world, it is often considered
beneficial to reduce levels of subcutaneous fat. For example,
in running events (or events where the body is not
supported), excess body weight has been shown to signifi-
cantly decrease relative V
max and performance during
a running test as a direct consequence of an increased energy
cost of running at submaximal speeds (8). Additionally, in
sports where body mass is accelerated against gravity, a more
lean muscle mass would be advantageous for performance
and energetic consumption. This is not to mention the effect
of body composition on cardiovascular risk factors and mor-
tality for the average person (27). It would be tempting to
suggest that the possible mechanism for an increased fat loss
in the LR group may be linked to the greater internal phys-
iological stress on the muscle, because strenuous resistive
exercise may elevate postexercise metabolic rate for a pro-
longed period and may enhance postexercise lipid oxidation
(31). However, more recently, Singhal et al. (44) found that
there was no significant difference in postprandial lipemia in
groups undertaking either moderate-intensity (MI) or high-
intensity (HI) resistance exercise. An alternative explanation
therefore for the physiological processes involved is linked
with the fact that acute resistance exercise has been shown
to increase adenosine monophosphate activated protein
kinase (AMPK) activity (9), which in turn has also been
shown to mediate effects of interleukin-6-stimulated increases
in glucose disposal and free fatty acid oxidation. Further,
AMPKa2 activity has been shown to be intensity dependent
(7); therefore, training at longer muscle lengths could affect
upstream factors of adiposity.
A second aim of the study was to determine if there was a
differential response to detraining between the training
groups. Both training groups showed that detraining period
resulted in significant losses at weeks 10 and 12 (p= 0.001,
= 0.34) in all measured parameters. Although generally
there was no significant difference between groups, the LR
group consistently exhibited a trend (p= 0.07, pe
= 0.32)
toward greater absolute and relative decrements in muscle
dimensional parameters over the 4-week detraining period.
This is in agreement with the findings of a previous study
(47) that reported that after 12 weeks of RT, a group of older
adults performing HI training increased total thigh CSA and
strength to a greater (p,0.05) extent than an MI training
group did. After a subsequent 12 weeks of detraining, total
relative thigh CSA and strength in the HI group diminished
significantly more than that in the MI group. Despite these
reductions, HI group strength and CSA remained signifi-
cantly greater than in the MI group because of greater initial
adaptations. In this study in terms of average VL aCSA
across the 3 sites, there was a decrease from 44 613 to
25 611% above baseline between weeks 8 and 12 in the
LR group, whereas SR decreased from 21 68% at weeks 8–
10 67% at week 12. Therefore the relative changes in the
aCSA to the LR group after 4 weeks of detraining (25 6
11%) are still superior to those made by the SR immediately
posttraining (21 68%). This suggests that although greater
initial gains may be lost at a greater rate, training using
a relatively wider ROM may still confer an advantage for
the longer term. This is evident in the strength data where
the LR group was significantly stronger until the conclusion
of the detraining period, whereas the SR group was not
significantly stronger compared with the pretraining data,
at week 10. It is difficult to say why greater gains are lost
more rapidly, such as in the LR group, but it may be because
of an inability to stimulate sufficient protein synthesis to
support a larger muscle mass. One would not expect to
observe a difference in daily protein synthetic rate between
groups with no change in activity levels and dietary habits
(21). Therefore, basal protein synthetic rates would support
a greater relative percentage of a smaller muscle mass than
a larger mass. Also, because resistance exercise causes per-
turbations to the intramuscular environment, and there are
subsequent adaptations, a new homeostatic point is reached,
where only a greater stimulus than the original will stimulate
further adaptations (23). The LR group may have set a higher
threshold to maintain adaptations, where daily activity did
not disturb the internal muscle environment as much as in
the SR group with a lower threshold. Indeed to reiterate,
although the face value load was similar in the 2 groups
(80% 1RM in both cases), the internal loads experienced are
in fact greater under a relatively wide ROM, and therefore,
because the phosphorylation of extracellular signal-regulated
kinase 1 and 2 and the 38-kDa stress-activated protein kinase
Journal of Strength and Conditioning Research
VOLUME 28 | NUMBER 1 | JANUARY 2014 | 253
Copyright © National Strength and Conditioning Association Unauthorized reproduction of this article is prohibited.
(p38) both appear to be intensity dependent (41) could be
a contributing factor to the difference in cellular response
and adaptation.
It should however be noted that in this study, although
the ROM has been presented as different, the manner in
which the 2 training groups were required to hold the
contractions (over 2 seconds) means that the greatest
difference in the loads experienced by the quadriceps muscle
was because of the internal joint architecture. In other words,
the difference between the 2 training protocols was not so
much owing to the ROM (thought this differed at the start of
the movement) but to the length of the muscle when the
muscle group was experiencing the “isometric hold” phase of
the exercise. Nevertheless, future studies should aim to deter-
mine whether in making the internal loads comparable the
effects of training at the relatively elongated muscle length
we describe here still exhibit the advantage over training at
a relatively shortened muscle length. The authors do also
recognize that in covering a greater ROM the muscle is
loaded for a longer duration in LR (i.e., 0.25–0.50 seconds).
However, previous studies (2) have concluded that measures
of work production during RT do not directly scale with the
adaptation responses seen in skeletal muscle. Furthermore,
it is difficult to give substance to a mechanism whereby
such a small difference in duration of loading (i.e., load-time
product) would lead to serial sarcomerogenesis and give rise
to such striking differences in fascicle length.
In summary, after 8 weeks of RT and 4 weeks of detraining
over different ROM (and thus implied average muscle lengths),
not only were there significant morphological differences
between the 2 groups after training but also the muscle
strength was enhanced to a greater extent after training at
a larger rather than a narrow ROM. Moreover, there was
a significant difference between groups in muscle architec-
ture, with fascicle length increments greater when training
over a large ROM, supporting the notion that muscle length
(or excursion) has a major influence on fascicle length. The
implications of the results may be useful in athletic training
and also deter athletes from reducing their ROM during
exercises to accommodate greater external loads.
In the field of practice, when choosing an ROM in which
a resistance exercise should be performed, muscle mechanics
must also be considered. We have shown that RT protocols
that enforce a wider ROM enhance the muscle character-
istics that influence force and power production to a greater
extent than protocols where the ROM is not as extensive.
A common error in practice is allowing the ROM to be
compromised to accommodate a greater absolute external
load, in an attempt to increase the stress of mechanical
loading. Following this, it is important for the coach to
reinforce a more complete ROM, even when absolute load
maybe reduced, to provide a greater internal stress and more
potent stimulus for adaptation. Optimization of training
mechanics could therefore potentially reduce the time spent
in the gymnasium achieving sporting and performance goals,
because training time and exercise volume constraints are
pivotal considerations in the periodization of training.
Adherence to a greater ROM also provides a better long-
term prognosis for retention of training adaptations, for
example, after prolonged bed rest and immobilization
(caused by illness and injury) or indeed during tapering.
The authors are ever indebted to the study populations
without whom none of this work would have been possible.
The authors are also grateful for the continued support from
the Institute for Performance Research.
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Journal of Strength and Conditioning Research
VOLUME 28 | NUMBER 1 | JANUARY 2014 | 255
Copyright © National Strength and Conditioning Association Unauthorized reproduction of this article is prohibited.
... Some other studies have investigated regional muscle hypertrophy between the FI-NALROM and the FULLROM protocols [14,18,31]. Bloomquist et al. [18] reported greater hypertrophy in the middle and distal regions of the anterior quadriceps femoris in a group of young men performing the back squat for 12 weeks in a FULLROM group compared to the FINALROM group. ...
... Bloomquist et al. [18] reported greater hypertrophy in the middle and distal regions of the anterior quadriceps femoris in a group of young men performing the back squat for 12 weeks in a FULLROM group compared to the FINALROM group. Similarly, McMahon et al. [31] reported greater distal vastus lateralis hypertrophy in a group of young men and women performing a variety of lower limb exercises in a FULLROM versus a FINALROM over an 8-week training period. Pedrosa et al. [14] showed greater distal muscle hypertrophy of rectus femoris and vastus lateralis muscles after training in FULLROM compared to FINALROM. ...
... Thus, we hypothesize that training in the INITIALROM promotes a heightened physiological response at the distal portion of the muscle, thereby leading to greater muscle protein increase in this region. Previous research supports our findings [7,14,18,31]; however, no attempts were made to explore mechanisms involved, which requires further investigation. ...
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Objective: The effects of ROM manipulation on muscle strength and hypertrophy response remain understudied in long-term interventions. Thus, we compared the changes in strength and regional muscle hypertrophy after training in protocols with different ranges of motion (ROM) in the seated dumbbell preacher curl exercise using a within-participant experimental design. Design and methods: Nineteen young women had one arm randomly assigned to train in the initial ROM (INITIALROM: 0°–68°; 0° = extended elbow) while the contralateral arm trained in the final ROM (FINALROM: 68°–135°), three times per week over an eight-week study period. Pre- and post-training assessments included one repetition maximum (1RM) testing in the full ROM (0°–135°), and measurement of biceps brachii cross-sectional area (CSA) at 50% and 70% of humerus length. Paired t-tests were used to compare regional CSA changes between groups, the sum of CSA changes at 50% and 70% (CSAsummed), and the strength response between the training protocols. Results: The INITIALROM protocol displayed a greater CSA increase than FINALROM protocol at 70% of biceps length (p = 0.001). Alternatively, we observed similar increases between the protocols for CSA at 50% (p = 0.311) and for CSAsummed (p = 0.111). Moreover, the INITIALROM protocol displayed a greater 1RM increase than FINALROM (p < 0.001). Conclusions: We conclude that training in the initial angles of elbow flexion exercise promotes greater distal hypertrophy of the biceps brachii muscle in untrained young women. Moreover, the INITIALROM condition promotes a greater dynamic strength increase when tested at a full ROM compared to the FINALROM.
... The decrease in fiber length change per whole muscle length change induced by fiber rotation has important functional implications, including increasing fiber force according to force-length and force-velocity relationships as well as reducing the magnitude of acute exercise-induced damage and thus muscle fiber functional decline during repetitive eccentric contractions (3). Additionally, reduced fiber length change resulting in an increased mean fiber length during contraction might also speculatively enhance the hypertrophic stimulus to repeated bouts of contractions, given that training at longer muscle (or muscle fiber) lengths is associated with greater increases in muscle mass (4)(5)(6). ...
... The increased fiber strain has also resulted in greater whole-muscle hypertrophy after a period of training (4-6) and increased resting sarcomere length (12). Thus, the greater fascicle strain observed at longer muscle lengths might partly explain the greater muscle hypertrophic responses observed when training at long muscle lengths using consecutive concentric-eccentric contraction repetitions (4,5). Conversely, increased fiber strain, during eccentric contractions in Copyright © 2023 by the American College of Sports Medicine. ...
Purpose: The present study compared the effects of contraction intensity (submaximal vs. maximal) and mode (concentric vs. eccentric) on biceps femoris long head (BFlh) fascicle lengthening, rotation, and architectural gear ratio at long and short muscle lengths. Methods: Data were captured from 18 healthy adults (10 men and 8 women) without history of right hamstring strain injury were used in the study. BFlh fascicle length (Lf) and angle (FA) and muscle thickness (MT) were assessed in real time using two serially aligned ultrasound devices whilst submaximal and maximal concentric and eccentric isokinetic knee flexions were performed at 30°/s. Ultrasound videos were exported and edited to create a single, synchronized video and three fascicles were analyzed through the range of motion (10°-80°). Changes (Δ) in Lf, FA, MT and muscle gear at long (60-80° knee angle; 0° = full knee extension) and short (10°-30°) muscle lengths and across the full knee flexion range were measured and compared. Results: Greater ΔLf was observed at long muscle length (p < 0.001) during both submaximal and maximal eccentric and concentric contractions. When the full length range was analyzed, a slightly greater ΔMT was observed in concentric contractions (p = 0.03). No significant differences between submaximal and maximal contractions were observed for ΔLf, ΔFA or ΔMT. No changes were detected in the calculated muscle gear between muscle lengths, intensities or conditions (p > 0.05). Conclusions: Although gear ratio ranged ~1.0-1.1 under most conditions, the increased fascicle lengthening observed at long muscle lengths might influence acute myofiber damage risk but also speculatively play a role in chronic hypertrophic responses to training.
... A amplitude de movimento demonstrou ligação com a hipertrofia muscular somente nos membros inferiores em relação a amplitudes totais, nos músculos do tronco seu resultado é inconclusivo até o presente momento. Notamos que a literatura é escassa no tópico, porém, evidências sugerem que amplitudes parciais resultem em dores e desconfortos nas articulações, o que não seria aconselhado no longo prazo 58,59,60,74,73 . Entre as forças desta revisão podemos citar: a) Todos os estudos analisados foram publicados em revistas científicas de qualidade, considerando as métricas de impacto como o fator de impacto (JCR); b) A maioria dos estudos utilizados mensuraram a hipertrofia muscular de maneira direta, por meio de ultrassom, ressonância magnética, biópsia muscular, ou tomografia computadorizada; c) A maioria dos estudos foram publicados na última década. ...
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As recomendações para o treinamento resistido partem de diretrizes como o ACSM e NSCA para as populações em geral, sendo encorajado a sua prática, a qual leva a benefícios à saúde física e mental. Nessa revisão narrativa, foi analisada a literatura atual sobre as variáveis do treinamento resistido (TR) e sua relação com a hipertrofia muscular, primeiramente, abordando os resultados acerca de cada variável de maneira isolada, posteriormente discutindo os resultados com revisões sistemáticas sobre cada variável isoladamente, e por último, chegando a um consenso do papel de cada variável como um conjunto, e seu impacto na hipertrofia muscular. Em nossos achados encontramos uma relação do volume com a hipertrofia, a frequência como ferramenta para distribuição do volume, um amplo espectro de intensidades que resultam em resultados equivalentes, a ordem e seleção dos exercícios como recurso para hipertrofia localizada, ações excêntricas superiores a ações concêntricas, intervalos como uma maneira de aumentar o volume, e a amplitude de movimento permanece necessitando de mais estudos para relacionar seu papel com a hipertrofia muscular.
... For example, McMahon et al. (82) reported that muscle size (normalised physiological cross-sectional area allometrically scaled to body mass) reduced significantly (−6 ± 8%) during a 2-week period of cessation following 8-weeks of resistance training. The reduction in muscle size is in line with previous studies utilising measurements of anatomical CSA in recreationally active participants (83,84). Conversely, Hwang et al. (85) reported no significant reductions in lean mass (utilising dualenergy x-ray absorptiometry) or rectus femoris CSA measured with ultrasound following a 2-week cessation period after a 4-week period of resistance training in resistance-trained individuals. ...
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Deloading refers to a purposeful reduction in training demand with the intention of enhancing preparedness for successive training cycles. Whilst deloading is a common training practice in strength and physique sports, little is known about how the necessary reduction in training demand should be accomplished. Therefore, the purpose of this research was to determine current deloading practices in competitive strength and physique sports. Eighteen strength and physique coaches from a range of sports (weightlifting, powerlifting, and bodybuilding) participated in semi-structured interviews to discuss their experiences of deloading. The mean duration of coaching experience at ≥ national standard was 10.9 (SD = 3.9) years. Qualitative content analysis identified Three categories: definitions, rationale, and application. Participants conceptualised deloading as a periodic, intentional cycle of reduced training demand designed to facilitate fatigue management, improve recovery, and assist in overall training progression and readiness. There was no single method of deloading; instead, a reduction in training volume (achieved through a reduction in repetitions per set and number of sets per training session) and intensity of effort (increased proximity to failure and/or reduction in relative load) were the most adapted training variables, along with alterations in exercise selection and configuration. Deloading was typically prescribed for a duration of 5 to 7 days and programmed every 4 to 6 weeks, although periodicity was highly variable. Additional findings highlight the underrepresentation of deloading in the published literature, including a lack of a clear operational definition.
... Both full and partial ROMs movements have shown a transfer of training effect. However, full ROM training appears to develop qualities underlying sport performance such as muscle cross-sectional area (CSA) and potentially strength to a greater degree than only partial movements [110,114]. These muscular adaptations in "capacity" can provide athletes a greater capability to develop force thus possibly increasing their potential to benefit from more specific training in later phases. ...
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Specificity has two major components: A strength-endurance continuum (S-EC) and adherence to principles of Dynamic Correspondence. Available evidence indicates the existence of the S-EC continuum from two aspects. Indeed, the S-EC exists, particularly if work is equated as a high load low repetition scheme at one end (strength stimulus) and high volume (HIEE stimulus) at the other. Furthermore, some evidence also indicates that the continuum as a repetition paradigm with high-load, low repetition at one end (strength stimulus) and a high repetition, low load at the other end. The second paradigm is most apparent under three conditions: (1) ecological validity—in the real world, work is not equated, (2) use of absolute loads in testing and (3) a substantial difference in the repetitions used in training (for example 2–5 repetitions versus ≥10 repetitions). Additionally, adherence to the principles and criteria of dynamic correspondence allows for greater “transfer of training” to performance measures. Typically, and logically, in order to optimize transfer, training athletes requires a reasonable development of capacities (i.e., structure, metabolism, neural aspects, etc.) before more specific training takes place
... For example, McMahon et al. (2019) reported that muscle size (normalized physiological cross-sectional area allometrically scaled to body mass) reduced significantly (−6 ± 8%) during a 2-week period of cessation following 8-weeks of resistance training. The reduction in muscle size is in line with previous studies utilising measurements of anatomical CSA in recreationally active participants (McMahon et al., 2014;Yasuda et al., 2015). Conversely, Hwang et al. (2017) reported no significant reductions in lean mass (utilising dual-energy x-ray absorptiometry) or rectus femoris CSA measured with ultrasound following a 2-week cessation period after a 4-week period of 36 resistance training in resistance-trained individuals. ...
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Evaluating anatomical contribution to performance can build an understanding of muscle mechanics and guide physical preparation. While the impact of anatomy on muscular performance is well studied, the effects of regional quadriceps architecture on rapid torque expression are less clear. Regional (proximal, middle, distal) quadriceps (vastus lateralis, rectus femoris, lateral and anterior vastus intermedius) thickness (MT), pennation angle (PA), and fascicle length (FL) of 24 males (48 limbs) were assessed via ultrasonography. Participants performed isometric contractions at 40º, 70º, and 100º of knee flexion to evaluate rate of torque development from 0-200 ms (RTD 0 − 200 ). Measurements were repeated on three separate occasions with the greatest RTD 0 − 200 and average muscle architecture measures used for analysis. Linear regression models predicting angle-specific RTD 0 − 200 from regional anatomy provided adjusted simple and multiple correlations (√adjR ² ) with bootstrapped compatibility limits to assess magnitude. Mid-rectus femoris MT (√adjR ² = 0.41–0.51) and mid-vastus lateralis FL (√adjR ² = 0.41–0.45) were the best single predictors of RTD 0 − 200 , and the only measures to reach acceptable precision with 99%CL. Small simple correlations were found across all regions and joint angles between RTD 0 − 200 and vastus lateralis MT (√adjR ² = 0.28 ± 0.13; mean ± SD), vastus lateralis FL (√adjR ² = 0.33 ± 0.10), rectus femoris MT (√adjR ² = 0.38 ± 0.10), and lateral vastus intermedius MT (√adjR ² = 0.24 ± 0.10). Multiple correlations are reported within the article. Researchers should measure mid-region rectus femoris MT and vastus lateralis FL to efficiently and robustly evaluate potential anatomical contributions to changes in rapid knee extension torque expression.
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Whether there is an optimal range of motion (ROM) to induce muscle hypertrophy remains elusive, especially for gastrocnemius. This study aimed to compare the changes in gastrocnemius muscle thickness between calf raise exercise performed with full ROM (FULLROM), partial ROM performed in the initial (INITIALROM), and final (FINALROM) portions of the ROM. Forty-two young women performed a calf training program for 8 weeks, 3 d·wk–1, with differences in the calf raise ROM configuration. The calf raise exercise was performed in a pin-loaded horizontal leg-press machine, in 3 sets of 15–20 repetitions maximum. The subjects were randomly assigned to 1 of the 3 groups: FULLROM (ankle: -25º to +25º), INITIALROM (ankle: -25º to 0º), and FINALROM (ankle: 0º to +25º), where 0º was defined as an angle of 90º of the foot with the tibia. The muscle thickness measurements of medial and lateral gastrocnemius were taken via B-mode ultrasound. INITIALROM elicited greater medial gastrocnemius increases than FULLROM and FINALROM (INITIALROM = +15.2% vs. FULLROM = +6.7% and FINALROM = +3.4%; P ≤ 0.009). Furthermore, INITIALROM elicited greater lateral gastrocnemius increases than FINALROM (INITIALROM = +14.9% vs. FINALROM = +6.2%; P < 0.024) but did not significantly differ from FULLROM (FULLROM = +7.3%; P = 0.060). The current results suggest that calf training performed at longer muscle lengths may optimize gastrocnemius muscle hypertrophy in young women. Therefore, when prescribing hypertrophy-oriented training, the inclusion of the calf raise exercise performed with partial ROM in the initial portion of the excursion should be considered.
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Resistance exercise range of motion (ROM) influences muscular adaptations. However, there are no consistent practical guidelines about the optimal ROM for maximizing muscle hypertrophy. The objective of the present paper was to systematically review the literature for studies that compared the effects of full ROM (fROM) and partial ROM (pROM) on muscle hypertrophy. PubMed/MEDLINE, Scopus, and Web of Science databases were searched to identify articles from the earliest record up to and including April 2022. We calculated the effect size (ES) scores of the variables of interest. Eleven studies were included in the review. fROM and pROM performed in the initial part of the ROM elicited greater muscle hypertrophy of the rectus femoris, vastus lateralis, biceps brachii and brachialis distal sites (between-groups ES: 0.20–0.90) than pROM performed in the final part of the ROM. fROM elicited greater muscle growth on the gluteus maximus and adductors than pROM in the final part of the ROM (between-groups ES: 0.24–0.25). Initial pROM produced more favorable proximal rectus femoris hypertrophy than fROM (between-group ES: 0.35–0.38). pROM in the middle part of the ROM elicited greater triceps brachii hypertrophy than fROM (between-groups ES: 1.21). In conclusion, evidence suggests that when training at a longer muscle length—through either a pROM or fROM—some muscles, such as the quadriceps femoris, biceps brachii and triceps brachii tend to experience optimal growth. Thus, the use pROM in the initial part of the excursion in combination with fROM training should be considered when prescribing hypertrophy-oriented resistance training programs.
Objective: The objective of this blinded parallel arm randomized controlled trial was to investigate the effect of resistance training (RT) on pain, maximal strength, and shoulder function in breast cancer survivors (BCS) with persistent pain after treatment. Methods: Twenty BCS with self-reported pain ≥1.5 years after treatment were randomized to an experimental group (EXP, n = 10), who performed a supervised progressive total body heavy RT program 2x/week for 12 weeks, or a control group (CON, n = 10) who was instructed to continue their everyday life. Perceived pain intensity (PI), pressure pain thresholds (PPT), one-repetition maximum (1RM) and active range of motion (ROM) were collected pre and post intervention and at three months follow up. Results: There was a significant 11% decrease in peak PI (P < 0.05) for both groups, a significant 48% increase in 1RM (P < 0.05) and a significant 35% increase in PPTs (P < 0.001) for EXP, but not for CON. For EXP, maximal strength at follow up was still significantly greater than at pre (P < 0.05), whereas PPTs had reverted to baseline levels. There was no change in active ROM (P < 0.05), and no change in arm circumference (P < 0.05). Conclusions: RT had a significant effect on 1RM and PPTs of BCS with persistent pain after treatment, demonstrating both a functional and analgesic effect of progressive RT in this population. Strength was largely maintained after detraining, whereas PPT levels were not, indicating that the process of RT rather than the gain in strength may be associated with analgesia.
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It is commonplace for people involved in recreational weight training to limit squat depth to lift heavier loads. This study compares differences in movement kinetics when squatting in the full range of motion (FROM) vs. partial range of motion (PROM). Ten men with a 1-year minimum of resistance training attended 4 sessions each comprising 4 sets of squats following one of FROM for 10 repetitions (FROM10) at an intensity of 67% 1 repetition maximum (1RM) FROM squat, PROM for 10 repetitions (PROM10) at 67% 1RM PROM squat, FROM for 5 repetitions (FROM5) at 83% FROM squat or PROM for 5 repetitions (PROM5) at 83% 1RM PROM squat. Movement velocity was not specified. Squat kinetics data were collected using an optical encoder. Differences between conditions were analyzed by repeated-measures analysis of variance and expressed as mean differences and standardized (Cohen) effect sizes with 95% confidence limits. The PROM5 power was substantially more than the PROM10 (98 W, -21 to 217; mean, lower and upper 95% confidence limits), FROM5 (168 W, 47-289), and FROM10 (255 W, 145-365). The force produced during PROM5 was substantially more than PROM10 (372 N, 254-490), FROM5 (854 N, 731-977), and FROM10 (1,069 N, 911-1227). The peak velocity produced during FROM10 was substantially more than FROM5 (0.105 m·s(-1), 0.044-0.166), PROM10 (0.246 m·s(-1), 0.167-0.325), and PROM5 (0.305 m·s(-1), 0.228-0.382). The FROM5 was substantially more than FROM10 (86 J, 59-113), PROM5 (142 J, 90-194), and PROM10 (211 J, 165-257). Therefore, either range of motion can have practical implications in designing resistance training programs depending on if the training goal is related to power and force development, maximizing work output or speed. Moderate-load PROM training, common among recreational weight trainers, is unlikely to provide higher movement kinetics.
Three high-skilled powerlifters performed parallel squats with different burden weights. Using a sagittal plane biomechanical model, the moments of force about the bilateral axes of the lumbo-sacral, hip, knee, and ankle joints were determined. A local biomechanical model of the knee was used in order to calculate the knee joint forces induced. The greatest moments were found in the lumbo-sacral joint. The maximum hip moment was greater than that of the knee moment which was greater than the ankle moment. The knee moment had a flexing direction and reached its maximum at the deepest position of the squat, while the lumbo-sacral and hip moments were found to reach their maxima during the first half second of the ascent. One lift that caused a bilateral quadriceps tendon rupture was stimulated and was found to give a maximum knee flexing moment ranging between 335 Nm and 550 Nm. This moment induced a force in each quadriceps tendon of between 10.9 kN and 18.3 kN at the occasion of rupture.
SUMMARY In order to stimulate further adaptation toward specific training goals, progressive resistance training (RT) protocols are necessary. The optimal characteristics of strength-specific programs include the use of concentric (CON), eccentric (ECC), and isometric muscle actions and the performance of bilateral and unilateral single- and multiple-joint exercises. In addition, it is recommended that strength programs sequence exercises to optimize the preservation of exercise intensity (large before small muscle group exercises, multiple-joint exercises before single-joint exercises, and higher-intensity before lower-intensity exercises). For novice (untrained individuals with no RT experience or who have not trained for several years) training, it is recommended that loads correspond to a repetition range of an 8-12 repetition maximum (RM). For intermediate (individuals with approximately 6 months of consistent RT experience) to advanced (individuals with years of RT experience) training, it is recommended that individuals use a wider loading range from 1 to 12 RM in a periodized fashion with eventual emphasis on heavy loading (1-6 RM) using 3- to 5-min rest periods between sets performed at a moderate contraction velocity (1-2 s CON; 1-2 s ECC). When training at a specific RM load, it is recommended that 2-10% increase in load be applied when the individual can perform the current workload for one to two repetitions over the desired number. The recommendation for training frequency is 2-3 dIwkj1 for novice training, 3-4 dIwkj1 for intermediate training, and 4-5 dIwkj1 for advanced training. Similar program designs are recom- mended for hypertrophy training with respect to exercise selection and frequency. For loading, it is recommended that loads corresponding to 1-12 RM be used in periodized fashion with emphasis on the 6-12 RM zone using 1- to 2-min rest periods between sets at a moderate velocity. Higher volume, multiple-set programs are recommended for maximizing hypertrophy. Progression in power training entails two general loading strategies: 1) strength training and 2) use of light loads (0-60% of 1 RM for lower body exercises; 30-60% of 1 RM for upper body exercises) performed at a fast contraction velocity with 3-5 min of rest between sets for multiple sets per exercise (three to five sets). It is also recommended that emphasis be placed on multiple-joint exercises especially those involving the total body. For local muscular endurance training, it is recommended that light to moderate loads (40-60% of 1 RM) be performed for high repetitions (915) using short rest periods (G90 s). In the interpretation of this position stand as with prior ones, recommendations should be applied in context and should be contingent upon an individual's target goals, physical capacity, and training
The relationship between hip and knee joint load and quadriceps muscle activity during squatting exercise to different depths was studied. Eight young national class Olympic weightlifters performed squatting exercise to 4 different knee flexion angles; 45°, 90°, parallel and deep squats. They held a barbell across their shoulders with a weight of 65% of their one-repetition maximum. The loading moments of force about the hip and knee joints were calculated using a semidynamic method. Video was used for motion recording and electromyograhy for recording activity from die vastus lateralis, rectus femoris and biceps femoris muscles. The loading moment on the hip joint increased significantly from the 90° squat to the parallel, but there was no difference between the parallel and the deep. For the knee joint, there was no difference between the 45°, 90° and parallel, but for the deep squat the loading moment increased significantly. The muscular activity generally increased with increasing squatting depth, but mere were only minor insignificant differences between the parallel and the deep squats. We conclude that knee joint load can be limited by doing parallel instead of deep squats and that this will not decrease quadriceps muscle activity. To limit hip moment, the squat should not be deeper than 90°.
The effect of time of day on the neural activation and contractile properties of the human adductor pollicis muscle was investigated in 13 healthy subjects. Two different times of day were chosen, corresponding to the minimum (7 h) and maximum (18 h) levels of strength. The force produced was compared with the associated electromyographic (EMG) activity during voluntary and electrically induced contractions in order to determine whether peripheral or central mechanisms play a dominant role in diurnal force fluctuation. The results indicated that the force produced during a maximum voluntary contraction (MVC) was significantly higher (+8.9%) in the evening than the morning. Since the increase in force of the MVC and the tetanic contraction (100 Hz) were similar, it is suggested that peripheral mechanisms are responsible for diurnal fluctuations in force. This conclusion is supported by the observation that central activation, tested by the interpolated twitch method during an MVC, did not change, and that the EMG was less per unit force in the evening. In addition to the increase in maximum twitch and tetanus force, significant changes in muscle contractile kinetics were also observed. The maximum rate of tension development and the relaxation of the twitch and tetanus increased in the evening, and the twitch contraction time (CT) and the time to half-relaxation (TR1/2) were reduced. Because the mean range of variation in skin temperature (2.6°C) observed over the course of the day was very low, this change cannot entirely explain those observed in muscle contractile properties. © 1999 John Wiley & Sons, Inc. Muscle Nerve 22: 1380–1387, 1999
The study of the underlying mechanisms by which cells respond to mechanical stimuli, i.e. the link between the mechanical stimulus and gene expression, represents a new and important area in the morphological sciences. Several cell types (‘mechanocytes’), e.g. osteoblasts and fibroblasts as well as smooth, cardiac and skeletal muscle cells are activated by mechanical strain and there is now mounting evidence that this involves the cytoskeleton. Muscle offers one of the best opportunities for studying this type of mechanotransduction as the mechanical activity generated by and imposed upon muscle tissue can be accurately controlled and measured in both in vitro and in vivo systems. Muscle is highly responsive to changes in functional demands. Overload leads to hypertrophy, whilst decreased load force generation and immobilisation with the muscle in the shortened position leads to atrophy. For instance it has been shown that stretch is an important mechanical signal for the production of more actin and myosin filaments and the addition of new sarcomeres in series and in parallel. This is preceded by upregulation of transcription of the appropriate genes some of which such as the myosin isoforms markedly change the muscle phenotype. Indeed, the switch in the expression induced by mechanical activity of myosin heavy chain genes which encode different molecular motors is a means via which the tissue adapts to a given type of physical activity. As far as increase in mass is concerned, our group have cloned the cDNA of a splice variant of IGF that is produced by active muscle that appears to be the factor that controls local tissue repair, maintenance and remodelling. From its sequence it can be seen that it is derived from the IGF gene by alternative splicing but it has different exons to the liver isoforms. It has a 52 base insert in the E domain which alters the reading frame of the 3′ end. Therefore, this splice variant of IGF-1 is likely to bind to a different binding protein which exists in the interstitial tissue spaces of muscle, neuronal tissue and bone. This would be expected to localise its action as it would be unstable in the unbound form which is important as its production would not disturb the glucose homeostasis unduly. This new growth factor has been called mechano growth factor (MGF) to distinguish it from the liver IGFs which have a systemic mode of action. Although the liver is usually thought of as the source of circulating IGF, it has recently been shown that during exercise skeletal muscle not only produces much of the circulating IGF but active musculature also utilises most of the IGF produced. We have cloned both an autocrine and endocrine IGF-1, both of which are upregulated in cardiac as well as skeletal muscle when subjected to overload. It has been shown that, in contrast to normal muscle, MGF is not detectable in dystrophic mdx muscles even when subjected to stretch and stretch combined with electrical stimulation. This is true for muscular dystrophies that are due to the lack of dystrophin (X-linked) and due to a laminin deficiency (autosomal), thus indicating that the dystrophin cytoskeletal complex may be involved in the mechanotransduction mechanism. When this complex is defective the necessary systemic as well as autocrine IGF-1 growth factors required for local repair are not produced and the ensuing cell death results in progressive loss of muscle mass. The discovery of the locally produced IGF-1 appears to provide the link between the mechanical stimulus and the activation of gene expression.