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Attentional Focus for Maximizing Muscle Development

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Brad J Schoenfeld at Lehman College
Brad J Schoenfeld
Bret Contreras
Bret Contreras
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Abstract

ATTENTIONAL FOCUS IS A WELL-RECOGNIZED ASPECT OF MOTOR LEARNING AND ITS USE HAS IMPORTANT IMPLICATIONS TO THE FITNESS PROFESSIONAL. THIS ARTICLE WILL DISCUSS HOW ATTENTIONAL FOCUS SHOULD BE DIRECTED TO MAXIMIZE MUSCULAR DEVELOPMENT.
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Evidence-Based Personal Training
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COLUMN EDITOR: Brad Schoenfeld, PhD, CSCS,
CSPS, NSCA-CPT
Attentional Focus for
Maximizing Muscle
Development: The
Mind-Muscle Connection
Brad J. Schoenfeld, PhD, CSCS, FNSCA
1
and Bret Contreras, MA, CSCS
2
1
Department of Health Sciences, Program of Exercise Science, City University of New York, Lehman College, New
York, New York; and
2
Sport Performance Research Institute, AUT University, Auckland, New Zealand
ABSTRACT
ATTENTIONAL FOCUS IS A WELL-
RECOGNIZED ASPECT OF MOTOR
LEARNING AND ITS USE HAS
IMPORTANT IMPLICATIONS TO THE
FITNESS PROFESSIONAL. THIS
ARTICLE WILL DISCUSS HOW
ATTENTIONAL FOCUS SHOULD BE
DIRECTED TO MAXIMIZE MUSCU-
LAR DEVELOPMENT.
A
ttentional focus is a well-
recognized aspect of motor
learning and its use has impor-
tant implications to the fitness profes-
sional. Simply stated, attentional focus
refers to what an individual thinks about
when performing a given movement or
activity . Two primary types of atten-
tional focuses have been identified:
internal and external. With an internal
focus, the individual thinks about bodily
movements during performance. Alter-
natively, an external focus directs the
exerciser’s attention to the environment.
For example, in the squat an internal
focus could be to “squeeze your glutes
as you ascend” whereas an external
focus could be to “drive the floor away
from your body.” This article will discuss
how attentional focus should be d irected
to maximize muscular development.
ATTENTIONAL FOCUS RESEARCH
A compelling body of research indi-
cates that performance-oriented tasks
are optimized by adopting an external
focus of attention. In a recent review of
literature encompassing over 50 pub-
lished studies on the topic, Wulf (12)
found that more than 90% of these
studies showed superior improvements
in motor learning when subjects used
an external compared with internal
focus. Beneficial effects were seen
across a wide variety of activities and
outcome measures, lending strong sup-
port for the use of an external focus
when the goal is to boost performance.
With respect to resistance training, the
performance-based superiority of an
external focus has been attributed to
an enhanced economy of movement
associated with greater force produc-
tion and reduced muscular activity (5).
However, whereas a more economical
movement pattern facilitates better skill
acquisition, it may not be optimal for
muscle development. Indeed, when
the goal is to maximize hypertrophy,
indirect evidence suggests that an inter-
nal focus may be the best approach.
Bodybuilders have long preached the
importance of developing a “mind-
muscle connection” when training. This
internally focused strategy involves visu-
alizing the target muscle and consciously
directing neural drive to the muscle dur-
ing exercise performance. Theoretically,
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Copyright ª National Strength and Conditioning Association. Unauthorized reproduction of this article is prohibited.
such an approach would increase acti-
vation of the target muscle while dimin-
ishing contribution from secondary
muscle movers. Indeed, research seems
to support this contention.
A number of studies have shown
greater activation of a given muscle
when subjects were instructed to adopt
an internal focus of attention. This has
been most prominently displayed in
the abdominal musculature. Karst and
Willett (3) found that subjects were
able to significantly alter mean electro-
myography (EMG) activity to either
the rectus abdominis or obliques by
consciously focusing on the respective
muscles during performance of the curl
up. Before engaging in exercise, sub-
jects in this study were instructed on
how to visualize either the rectus or
obliques and verbal reinforcement of
these instructions were provided dur-
ing performance. A control condition
involved focusing on the movement
itself without regard to any specific
muscles. These results are consistent
with research showing increased acti-
vation of the transversus abdominis
after instruction to tighten the pelvic
floor muscles (2). Similarly, Bressel
et al. (1) demonstrated that mean and
peak EMG amplitude were significantly
increased in both superficial and deep
abdominal musculature during the
squat when subjects were directed to
“brace yourself as if you were going to
be punched in the stomach.”
Findings of heightened EMG activity
from an internal focus have been noted
in other muscles as well. Lewis and
Sahrmann (4) showed that young
women were able to achieve greater
mean EMG activity of the gluteus
maximus and reduced activation of
the hamstrings when cued to contract
the gluteal muscles during perfor-
mance of the prone hip extension
(“Use your gluteal muscles to lift your
leg while keeping your hamstrings
muscles relaxed”). Moreover, the tim-
ing of activation was altered so that
the gluteus maximus was activated sig-
nificantly earlier during movement.
Likewise, research has shown that
intentionally focusing on the target
muscle resulted in higher activation
of the latissimus dorsi, pectoralis major,
biceps brachii, and triceps brachii (5,7–
9). Interestingly, evidence seems to
indicate that the increased activation
does not always coincide with reduc-
tions in the activity of secondary mus-
cle movers (7,8).
Although it remains unclear as to
whether increased muscle activation
translates into greater muscle protein
accretion, emerging research indicates
that this may in fact be the case. In a 2-
part experiment, Wakahara et al. (11)
first investigated acute muscle activation
in 12 untrained men after a single bout
of resistance training for the elbow ex-
tensors through T2-weighted magnetic
resonance imaging. The exercise proto-
col consisted of 5 sets of 8 repetitions of
lying triceps extensions with 90 seconds
rest between sets. Results showed sig-
nificantly greater activation in the prox-
imal and mid-portions of the triceps
brachii compared with the distal aspect.
Another 12 subjects were then recruited
to perform a 3-day-per-week program
consisting of the same routine used in
part 1 of the study. After 12 weeks of
regimented training, increases in muscle
cross-sectional area were found to be
well-correlated to the areas most acti-
vated by the exercise regimen. Follow-
up work by the same laboratory showed
similar results using different triceps bra-
chii exercises (10), which in combina-
tion provide evidence for an association
between activation levels and muscle
growth. It should be noted that these
studies did not attempt to investigate
muscle activation in conjunction with
altered attentional focus, so it is unclear
whether results would translate to the
adoption of an internal focus. Moreover,
the results of these studies are specific to
the triceps brachii and thus cannot nec-
essarily be generalized to other muscles.
Interestingly, the effectiveness of using
an internal focus is reduced when
training at higher loads. Snyder and
Fry (7) found that activation of the pec-
torals was amplified by 22% when
resistance-trained men were provided
with verbal instructions to focus on the
chest muscles during bench press at
50% 1 repetition maximum (1RM).
However, the magnitude of this effect
decreased to 13% when the same in-
structions were provided during per-
formance at 80% 1RM. This may be
a function of needing to exert greater
levels of force when training at heavier
loads, thereby altering one’s ability to
focus on the muscle being worked.
Moreover, in accordance with the size
principle, fewer motor units will be
available for the mind to influence with
heavy loading when compared with
lighter loads. This suggests that adopt-
ing an internal attentional focus with
very heavy loads (above 85–90% of
1RM) is unnecessary because it might
limit force production without enhanc-
ing muscle activation, but more
research is needed in subjects with
varying levels of experience to explore
this hypothesis.
PRACTICAL APPLICATIONS
Attentional f ocus should match the
goal of the task. Competitive sport
athletes should rely heavily on exter-
nal attentional focus in practice and
during games or matches. This in-
cludes powerlifters, weightlifters, or
strongmen seeking to set a 1RM or
to maximize force or tor que produc-
tion; basketball players or track &
field athletes seeking to maximize
jump height or distance; runners or
rowers seeking to improve economy;
and dart throwers, golfers, and pool
players seeking maximum accuracy.
Alternatively, when attempting to
maximize muscle activation, an inter-
nal focus of attention would seem to
be a better choice. Bodybuilders, phy-
sique athletes, and others seeking
maximal hypertrophy will conceiv-
ably benefit by focusing on the target
muscle during an exercise rather than
on the outcome or environment. It is
likely that the molecular signaling for
all 3 primary mechanisms of muscular
hypertrophy, namely mechanical ten-
sion, metabolic stress, and muscle
damage (6), are increased when the
exerciser focuses their attention inter-
nally, which could ultimately result in
greater muscular development for
a given exercise and load. The effects
Evidence-Based Personal Training
VOLUME 0 | NUMBER 0 | MONTH 2016
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of this strategy seem to be particularly
beneficial when training with rela-
tively light loads.
Conflicts of Interest and Source of Funding:
The authors report no conflicts of interest
and no source of funding.
Brad J. Schoenfeld is an assistant
professor in the exercise science program
at CUNY Lehman College and director
of their human performance laboratory.
Bret Contreras is currently pursuing
his PhD in Sports Science at the Auck-
land University of Technology in Auck-
land, New Zealand.
REFERENCES
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Fontana FE. Effect of instruction, surface
stability, and load intensity on trunk muscle
activity. J Electromyogr Kinesiol 19: e500–
e504, 2009.
2. Critchley D. Instructing pelvic floor
contraction facilitates transversus abdominis
thickness increase during low-abdominal
hollowing. Physiother Res Int 7: 65–75,
2002.
3. Karst GM and Willett GM. Effects of
specific exercise instructions on abdominal
muscle activity during trunk curl exercises.
J Orthop Sports Phys Ther 34: 4–12,
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4. Lewis CL and Sahrmann SA. Muscle
activation and movement patterns during
prone hip extension exercise in women.
J Athl Train 44: 238–248, 2009.
5. Marchant DC, Greig M, and Scott C.
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6. Schoenfeld BJ. The mechanisms of muscle
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7. Snyder BJ and Fry WR. Effect of verbal
instruction on muscle activity during the
bench press exercise. J Strength Cond Res
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8. Snyder BJ and Leech JR. Voluntary increase
in latissimus dorsi muscle activity during the
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9. Vance J, Wulf G, Tollner T, McNevin N, and
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learning: A review of 15 years. Int Rev
Sport Exerc Psychol 6: 77–104, 2013.
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... Focus of attention is considered an integral strategy in the field of motor learning. Focus of attention can be defined as what the subject thinks about while performing a movement or activity [12,13]. There are two basic strategies for focusing attention while performing a task: internal and external. ...
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... These findings are consistent with our own observations. Schoenfeld and Contreras [12] propose that an increase in muscle activity via internal focus is likely to be less effective at higher external loads, such as 80% 1RM. This is due to the greater recruitment of motor units at higher external loads, which results in a reduction in the number of motor units that can be selectively activated. ...
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  • May 2009
  • J ATHL TRAINING
The consistency of muscle activation order during prone hip extension has been debated. To investigate whether women use a consistent and distinguishable muscle activation order when extending the hip while prone and to explore the effects of verbal cues on muscle activation and movement. Single-session, repeated-measures design. University laboratory. Eleven healthy women (age = 27.7 +/- 6.2 years [range, 22-37 years]). We tested the participants under 3 conditions: no cues, cues to contract the gluteal muscles, and cues to contract the hamstrings muscles. We measured hip and knee angle and electromyographic data from the gluteus maximus, medial hamstrings, and lateral hamstrings while participants performed prone hip extension from 30 degrees of hip flexion to neutral. When not given cues, participants used the consistent and distinguishable muscle activation order of medial hamstrings, followed by lateral hamstrings, then gluteus maximus (195.5 +/- 74.9, 100.2 +/- 70.3, and 11.5 +/- 81.9 milliseconds preceding start of movement, respectively). Compared with the no-cues condition, the gluteal-cues condition resulted in nearly simultaneous onset of medial hamstrings, lateral hamstrings, and gluteus maximus (131.3 +/- 84.0, 38.8 +/- 96.9, and 45.1 +/- 93.4 milliseconds, respectively) (P > .059); decreased activation of the medial hamstrings (P < .03) and lateral hamstrings (P < .024) around the initiation of movement; increased activation of gluteus maximus throughout the movement (P < .001); and decreased knee flexion (P = .002). Compared with the no-cues condition, the hamstrings-cues condition resulted in decreased activation of the medial hamstrings just after the initiation of movement (P = .028) and throughout the movement (P = .034) and resulted in decreased knee flexion (P = .003). Our results support the contention that the muscle activation order during prone hip extension is consistent in healthy women and demonstrates that muscle timing and activation amplitude and movement can be modified with verbal cues. This information is important for clinicians using prone hip extension as either an evaluation tool or a rehabilitation exercise.
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Attentional focus and motor learning: A review of 15 years
Article
  • Sep 2013
Over the past 15 years, research on focus of attention has consistently demonstrated that an external focus (i.e., on the movement effect) enhances motor performance and learning relative to an internal focus (i.e., on body movements). This article provides a comprehensive review of the extant literature. Findings show that the performance and learning advantages through instructions or feedback inducing an external focus extend across different types of tasks, skill levels, and age groups. Benefits are seen in movement effectiveness (e.g., accuracy, consistency, balance) as well as efficiency (e.g., muscular activity, force production, cardiovascular responses). Methodological issues that have arisen in the literature are discussed. Finally, our current understanding of the underlying mechanisms of the attentional focus effect is outlined, and directions for future research are suggested.
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Nonuniform Muscle Hypertrophy: Its Relation to Muscle Activation in Training Session
Article
  • May 2013
  • MED SCI SPORT EXER
Purpose: Muscle hypertrophy in response to resistance training has been reported to occur nonuniformly along the length of the muscle. The purpose of the present study was to examine whether the regional difference in muscle hypertrophy induced by a training intervention corresponds to the regional difference in muscle activation in the training session. Methods: Twelve young men participated in a training intervention program for the elbow extensors with a multijoint resistance exercise for 12 wk (3 d · wk(-1)). Before and after the intervention, cross-sectional areas of the triceps brachii along its length were measured with magnetic resonance images. A series of transverse relaxation time (T2)-weighted magnetic resonance images was recorded before and immediately after the first session of training intervention. The T2 was calculated for each pixel within the triceps brachii. In the images recorded after the session, the number of pixels with a T2 greater than the threshold (mean + 1 SD of T2 before the session) was expressed as the ratio to the whole number of pixels within the muscle and used as an index of muscle activation (percent activated area). Results: The percent activated area of the triceps brachii in the first session was significantly higher in the middle regions than that in the most proximal region. Similarly, the relative change in cross-sectional area induced by the training intervention was also significantly greater in the middle regions than the most proximal region. Conclusion: The results suggest that nonuniform muscle hypertrophy after training intervention is due to the region-specific muscle activation during the training session.
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Effect of Verbal Instruction on Muscle Activity During the Bench Press Exercise
Article
  • Nov 2011
  • J STRENGTH COND RES
Recent research suggests that humans have some ability to selectively activate or relax some muscles during isometric or dynamic muscle actions without changing posture or position. This study sought to reveal whether trained athletes could isolate either the pectoral or triceps muscles, respectively, at different intensities when given verbal technique instruction. Eleven male Division III football players performed 3 sets of bench press at 50% 1-repetition max (1RM) and 80% 1RM while electromyographic (EMG) activity was recorded from the pectoralis major (PM), anterior deltoid (AD), and triceps brachii (TB). In the first set, the subjects performed the exercise without instruction. In the second set, the subjects were given verbal instructions to use only chest muscles. In the third set, the subjects were instructed to use only triceps muscles. Mean normalized root mean square EMG activity was calculated during 3 repetitions in each condition. Repeated-measures analysis of variance was used to detect differences from the preinstruction condition, with significance set to p ≤ 0.017 as indicated by a Bonferroni correction for multiple comparisons. During the 50% max lift with verbal instructions to focus on chest muscles, PM EMG activity increased by 22% over preinstruction activity (p = 0.005), whereas AD and TB activities were statistically unchanged. When the subjects were instructed to focus on only the triceps muscles, PM returned to baseline activity, whereas TB activity was increased by 26% (p = 0.005). When the lift was increased to 80% max, PM and AD activities were both increased with verbal instructions to use only chest muscles. The TB activity was unchanged during the 80% lifts, regardless of instructions. In conclusion, it is found that verbal technique instruction is effective in shifting muscle activity during a basic lift, but it may be less effective at higher intensities.
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Association between regional differences in muscle activation in one session of resistance exercise and in muscle hypertrophy after resistance training
Article
  • Aug 2011
  • EUR J APPL PHYSIOL
The purpose of this study was to examine if the regional difference in muscle hypertrophy after chronic resistance training is associated with muscle activation after one session of resistance exercise. Twelve men performed one session of resistance exercise of elbow extensors. Before and immediately after the exercise, transverse relaxation time (T2)-weighted magnetic resonance (MR) images of upper arm were recorded to evaluate the muscle activation along its length. In the MR images, T2 for the pixels within the triceps brachii muscle was quantified. The number of pixels with T2 greater than the threshold (mean + 1SD of T2 before the exercise) was expressed as the ratio to the number of pixels occupied by the muscle (%activated area). Another 12 subjects completed 12 weeks of training intervention (3 days per week), which consisted of the same program variables as used in the experiment for the T2 measurement. The cross-sectional areas of the triceps brachii before and after the training intervention were measured from MR images of upper arm. The %activated area of the triceps brachii induced by one session of the exercise was found to be significantly lower in the distal region than the middle and proximal regions. Similarly, the relative increase in muscle cross-sectional area after the 12 weeks of training intervention was significantly less in the distal region than the middle and proximal regions. The results suggest that the regional difference in muscle hypertrophy after chronic resistance training is attributable to the regional difference in muscle activation during the exercise.
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Voluntary Increase in Latissimus Dorsi Muscle Activity During the Lat Pull-Down Following Expert Instruction
Article
  • Oct 2009
  • J STRENGTH COND RES
It has been observed anecdotally that while performing the multijoint lat pull-down exercise, novice strength trainers often rely on the elbow flexors to complete the movement rather than fully utilizing the relevant back muscles such as the latissimus dorsi (LD) and teres major (TM). The primary aim of the study was to determine whether specific technique instruction could result in a voluntary increase in LD and TM electromyographic (EMG) activity with a concurrent decrease in the activity of the biceps brachii (BB) during the front wide-grip lat pull-down exercise. Eight women with little or no background in strength training were asked to perform lat pull-down exercise with only basic instruction, performing 2 sets of 3 repetitions at 30% max. After a brief rest, subjects then performed the same 2 sets of 3 repetitions following verbal technique instruction on how to emphasize the latissimus while de-emphasizing the biceps. EMG activity of the LD, TM, and BB were recorded, converted to root mean square, and normalized to the maximum isometric EMG (NrmsEMG). A significant increase was seen in Nrms EMG in the LD (p = 0.005) from the average of preinstruction NrmsEMG to the average of postinstruction NrmsEMG. No significant differences were observed between pre- and postinstruction muscle activity in the BB or TM. The results show that untrained individuals can voluntarily increase the activity of a specified muscle group during the performance of a multijoint resistance exercise, but the increase probably does not represent "isolation" of the muscle group through voluntary reduction of activity in complementary agonist muscles.
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Effect of instruction, surface stability, and load intensity on trunk muscle activity
Article
  • Dec 2009
The aim of this study was to assess the effect of verbal instruction, surface stability, and load intensity on trunk muscle activity levels during the free weight squat exercise. Twelve trained males performed a free weight squat under four conditions: (1) standing on stable ground lifting 50% of their 1-repetition maximum (RM), (2) standing on a BOSU balance trainer lifting 50% of their 1-RM, (3) standing on stable ground lifting 75% of their 1-RM, and (4) receiving verbal instructions to activate the trunk muscles followed by lifting 50% of their 1-RM. Surface EMG activity from muscles rectus abdominis (RA), external oblique (EO), transversus abdominis/internal oblique (TA/IO), and erector spinae (ES) were recorded for each condition and normalized for comparisons. Muscles RA, EO, and TA/IO displayed greater peak activity (39-167%) during squats with instructions compared to the other squat conditions (P=0.04-0.007). Peak EMG activity of muscle ES was greater for the 75% 1-RM condition than squats with instructions or lifting 50% of 1-RM (P=0.04-0.02). The results indicate that if the goal is to enhance EMG activity of the abdominal muscles during a multi-joint squat exercise then verbal instructions may be more effective than increasing load intensity or lifting on an unstable surface. However, in light of other research, conscious co-activation of the trunk muscles during the squat exercise may lead to spinal instability and hazardous compression forces in the lumbar spine.
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Instructing pelvic floor contraction facilitates transversus abdominis thickness increase during low-abdominal hollowing
Article
  • Jun 2002
Low abdominal hollowing in four-point kneeling is used clinically to test and rehabilitate transversus abdominis (TrA) but many people find this exercise difficult to perform. Contracting pelvic floor muscles (PF) during low abdominal hollowing may facilitate contraction of TrA. Thickness increase in the abdominal muscles during low abdominal hollowing has been measured with real-time ultrasound scanning and may indicate muscle contraction. The present study investigated the effect of instructing PF contraction on TrA thickness increase during low abdominal hollowing. Twelve females and eight males with no reported pelvic floor dysfunction or low back pain in the last two years were taught low abdominal hollowing in four-point kneeling. Subjects performed low abdominal hollowing with and without instruction to contract PF in random order. Transversus abdominis, obliquus internus (OI) and obliquus externus (OE) thickness were measured with ultrasound scanning at rest and during both tests. Mean increase in TrA thickness during low abdominal hollowing was 49.71% (SD 26.76%), during low abdominal hollowing with PF it was 65.81% (SD 23.53%). Paired Student's t-tests indicated a significant difference between tests (p = 0.015). There were no significant differences between tests for OE or OI thickness increase. Instructing healthy subjects to co-contract PF results in greater increase in TrA thickness during low abdominal hollowing in four-point kneeling. This may indicate greater contraction of TrA and thus be useful for clinicians training TrA. Further research could investigate the validity of change of thickness as a measure of abdominal muscle contraction, investigate the effect of instructing PF co-contraction on TrA in patients with low back pain and measure PF and TrA activity simultaneously.
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