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Breathe in and…breathe out? An investigation into the causal relationship between intra-
abdominal pressure, spine stability, and force production during weightlifting exercise.
A literature review by David Janett, Masters degree candidate in the applied physiology program at Teachers College, Columbia University, New York, NY, April 2016.
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Abstract Trainers play an integral role in the development and implementation of exercise
programs across numerous populations, ranging from rehabilitation patients to elite
athletes. Although copious medical and scientific texts provide specific protocols
regarding several elements of resistance training, including volume and intensity
recommendations, none of them offer clear guidelines for breathing technique (Lamberg
et al. 2010). It is hypothesized that raising intra-abdominal pressure (IAP), via a held
breath technique (not a true Valsalva maneuver), along with co-activation of certain trunk
musculature leads to an increase in lumbar spine stability, which in turn allows for gains
in force production during dynamic weightlifting. Research on this topic began with an
initial search on the Web of Science and PubMed databases. Key terms included
breathing, weightlifting, resistance training, and force production. The primary variables
involved were intra-abdominal pressure (IAP), intra-thoracic pressure (ITP), the Valsalva
maneuver, respiratory volumes (Vr), trunk muscle activation, and lumbar spine stability.
Exclusion criteria were minimal, save for subjects with injuries or existing pathologies.
The sum total of articles came to twenty-eight. There was significant research connecting
breathing patterns, IAP, and spine stability; and the held breath technique was
consistently championed as the most safe and effective method of developing both IAP
and spine stability. Co-contraction of key trunk muscles (particularly the transversus
abdominus, external and internal obliques, rectus abdominus, erector spinae, and
latissimus dorsi) appeared to contribute significantly to the development of IAP. There
was, however, a lack of research focusing on the relationship between IAP, spine
stability, and force production. Of the studies that did examine this association, several
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design flaws (mainly the employment of an isometric exertion and the lack of data
regarding IAP) undermined the applicability of the results. It is recommended that future
research focusing on IAP, spine stability, and force production be performed so that
stronger and more relevant conclusions can be made.
Key terms
Intra-abdominal pressure (IAP) – The degree of pressure in the abdominal cavity.
Intra-thoracic pressure (ITP) – The degree of pressure in the thoracic cavity.
Valsalva maneuver – A breathing pattern in which an individual inhales air and then
forcibly exhales air against a closed glottis.
Electromyography (EMG) – A method of measuring the electrical activity of skeletal
muscle.
Inspiratory volume (Vi) – The amount of inspired air during inhalation.
Expiratory volume (Ve) – The amount of expired air during exhalation.
Tidal volume (Vt) – The amount of air passing through the lungs during quiet breathing.
Spine stability – The body’s ability to resist spinal column posture aberrations.
Force production – The degree of physical force produced by an event or action.
Isometric exercise – Resistance exercise in which muscular contraction occurs and the
joint angle and muscle length do not change.
Dynamic exercise – Resistance exercise in which muscular contraction occurs and both
the joint angle and muscle length change.
Concentric contraction – A contraction in which the muscle shortens and generates force.
Eccentric contraction – A contraction in which the muscle faces resistance but is forced
to lengthen.
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Introduction This literature review is aimed towards fitness professionals and is intended to
demystify the variable of breath control as it relates to performance during resistance
training. Trainers play an integral role in the development and implementation of
exercise programs across numerous populations, ranging from rehabilitation patients to
elite athletes. In accordance with their certifications, they are expected to maintain
knowledge of current fitness industry trends and deliver safe and effective workouts to
their clients. There are numerous accredited fitness organizations in the United States
and all of them produce materials with up to date information on the many aspects of
personal training, such as cardiovascular programming and body composition
measurement. Although copious medical and scientific texts provide specific protocols
regarding several elements of resistance training, including volume and intensity
recommendations, none of them offer clear guidelines for breathing technique (Lamberg
et al. 2010). The dearth of data focusing on proper breath control leads both trainers and
untrained exercisers to refer to non-medical sources, often anecdotal evidence provided
via the Internet. These sources generally suggest inhaling during the eccentric
contraction and exhaling during the concentric contraction, with a brief moment of breath
holding at lift-off in an attempt to improve lumbar stability and thereby increase force
production (Lamberg et al. 2010). However, many powerlifters prefer to hold their
breath throughout the entirety of a lift in order to maximize force production.
Unfortunately, these contrasting recommendations are merely theoretical and
potentially dangerous, and the scientific data regarding possible correlations between
breathing patterns and force production remain scarce to nonexistent. In order to develop
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a correlation between breath control and force production, information on the many
variables involved must be organized so that a causal pathway can be established.
Although the outcome variable is clearly force production, the independent variables and
steps manipulating this outcome are not only numerous, they are intertwined
chronologically, making a detailed investigation of this subject even more essential. It is
hypothesized that raising intra-abdominal pressure (IAP), via a held breath technique (not
a true Valsalva maneuver), along with co-activation of certain trunk musculature leads to
an increase in lumbar spine stability, which in turn allows for gains in force production
during dynamic weightlifting. In this literature review, the anatomical, physiological,
and biomechanical factors of breathing and weightlifting will be discussed and
suggestions for further exploration of this topic will be offered.
Methods
Research on this topic began with an initial search on the Web of Science and
PubMed databases. Key terms included breathing, weightlifting, resistance training, and
force production. This led to the acquisition of six articles, all of which helped to steer
the review by highlighting the primary variables involved: intra-abdominal pressure
(IAP), intra-thoracic pressure (ITP), the Valsalva maneuver, respiratory volumes (Vr),
trunk muscle activation, and lumbar spine stability. The exclusion criteria were minimal
due to the non-epidemiological nature of this topic, and so articles dating back as far as
1980 were accepted. In addition, the inclusion standards of most experiments were fairly
liberal, with the primary discounting factor being some type of previous injury or existing
pathology. Researchers in this area of exercise science seem to welcome both generally
healthy and elite athletic populations into their studies.
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After developing a more in-depth understanding of these variables, a second
database search was performed, which produced eight more relevant articles. At this
point in the review process, the recurrence of several important authors and their
continuous citing of each other’s texts revealed a clear timeline of research. These
citations were recorded and employed in the third and last database search, in which the
titles of studies, rather than key terms and authors’ names, were used. This led to the
attainment of fourteen more articles, brining the number of relevant studies on this
subject to a sum total of twenty-eight.
Results
AUTHOR DATE # AGE GENDER FITNESS HISTORY
WEIGHT/HEIGHT
PROCEDURE MEASURES RESULTS
Cholewicki, J.
1999 10
24-32 NA No history of lower back pain (LBP).
avg 78 (14) kg and 177 (7) cm
Loading of trunk via a cable with subjects (w/and w/out a belt) seated in a jig that restricted motion at and below hip joint.
Trunk angle, spine stability, IAP, trunk movement, EMG activity, presence/absence of belt.
Presence of belt and raised IAP led to increase in trunk stiffness during flexion, extension, and lateral bending. The belt added 9-57% of trunk stiffness depending on IAP and trunk movement. Elevated IAP led to significant EMG activity in all trunk muscles.
Cholewicki, J.
2002 10
22-32 9 M 1 F No history of LBP.
avg 78 (14) kg and 177 (7) cm
Isometric trunk extension, flexion, and lateral bending.
IAP, ITP, spine stability, compression force, and EMG activity.
Correlation between spine stability and IAP. Correlation between EMG activity and IAP and ITP.
Cresswell, A.G.
1989 7 23-27 All M No history of LBP.
77-86 kg and 183-190 cm
Isometric trunk extension and flexion and a Valsalva.
IAP, EMG activity, isometric trunk torque.
High IAP in all movements. Low EMG in extension. IAP greatest during Valsalva.
Cresswell, A.G.
1992 6 26-30 All M Habitually active and no adiposity.
79 (3) kg and 1.82 (0.06) m
Isometric trunk extension and flexion and a Valsalva.
IAP, EMG activity, isometric trunk torque.
Correlation between IAP and transversus abdominal EMG. EMG activity of trunk was task specific.
7
Cresswell, A.G.
1994 7 24-30 All M Habitually active and no adiposity.
75 (3) kg and 1.79 (0.01) m
Sub-maximal sagittal lifting and lowering.
IAP, force, EMG activity, velocity.
EMG activity less during lowering than lifting. Correlation between IAP and force.
DePalo, V.A.
2004 8 27-61 All M 4 controls (C) and 4 trained (T).
C 67-86 kg and 167-180 cm T 71-91 kg and 165-180 cm
16 weeks of 4 days/week of workouts including situps and dumbbell bicep curls.
Pressures (transdiaphragmatic, inspiratory, expiratory, gastric), diaphragm thickness.
With training there were increases in transdiaphragmatic pressures 198-256 cmH20 (P<0.02), inspiratory pressure 134-171 (P<0.002), expiratory pressure 195-267 (P<0.002), gastric pressure 161-212 (P<0.03), diaphragm thickness 2.5-3.2 mm (P<0.001).
De Troyer, A.
1990 6 25-39 All M NA NA Voluntary respiratory efforts such as breathing, speaking, expulsive maneuvers, "belly in" maneuvers while seated.
Respiratory volume, EMG activity of 3 different abdominal muscles.
During voluntary respiratory efforts, the transversus contracted together with external obliques and rectus. During hyperoxic hypercapnia, activity in the transversus at ventilations 10-18.1/min occurred well before other abdominal muscles.
Gagnon, M.
1992 5 23-46 NA Varying degrees of experience.
58.2-78.2 kg and 156-174 cm
Lifting of 2 different loads under 3 varying conditions (slow-continuous, accelerated-continuous, accelerated-pause).
Load, condition, net moments at joints, spinal compression loading, work and energy transfer.
Joint muscular moments, spinal loading, work, and muscular utilization ratios increased with acceleration without benefits of improved energy transfer.
Hagins, M.
2004 11
20-40 M and F No history of LBP.
NA Straight leg and bent knee lifting efforts.
Breathing method, load, posture, IAP.
Significant effect of breath control (P<0.018) and load (P<0.002), but not posture (P<0.434) on IAP. Inhalation-hold led to greatest IAP (P< 0.000).
8
Hagins, M.
2005 20
NA M and F No history of LBP.
NA 9 lifts of a standard plastic milk crate.
Load, breathing method, inspiratory volume.
Increase in inspiratory volume prior to lift-off. Greater load led to greater inspiratory volume and more breath holding.
Hagins, M.
2006 33
20-40 13 M 20 F No history of LBP
NA Maximal isometric trunk exertion in knee bent position.
IAP, breathing method, force production.
Breath control did not significantly affect force (P=0.089) but did affect IAP (P=0.003). Low correlation between IAP and force (r =0.152-0.583).
Hodges, P.W.
1996 30
20-40 16 M 14 F 15 w/LBP and 15 control.
LBP 73.5 kg/174.1 cm and C 67.3 kg/173.3 cm
Shoulder flexion, abduction, and extension.
Direction of movement and EMG activity.
Transversus abdominal was the first muscle activated and was not influenced by direction. Subjects w/LBP had delayed transversus abdominal activity.
Hodges, P.W.
1999 8 21-29 All M Habitually active.
avg 78 (8) kg and 1.82 (0.04) m
Bilateral upper limb flexion, abduction, extension.
Direction of movement, EMG activity, IAP, displacement of centers of pressure and mass.
Small preparatory displacement of trunk in opposite direction of limb movement. Superficial muscles activated in response to direction, deep abdominals activated regardless of direction.
Hodges, P.W.
2003 11
0-1 NA Adolescent pigs (not a human study).
50-60 kg Intentional intervertebral displacement of L4 via a device and electrical stimulation of phrenic nerves.
IAP, EMG activity, intervertebral motion, spinal stiffness.
Increases in IAP via diaphragm/abdominal activation led to less displacement of L3/4 and increased stiffness of L4 during caudal displacement (but not rostral).
Hodges, P.W.
2005 3 30-44 NA Healthy. 58-87 kg and 172-187 cm
Tetanic stimulation of phrenic nerves.
IAP and spinal stiffness.
Tetanic stimulation led to increases in IAP (27-61% of max) and spinal stiffness (8-31% greater than at rest).
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Kawabata, M.
2010 21
avg 21.3
All M 10 trained and 11 control.
T avgs 76.7 and 64.4 kg and C avgs 170.2 and 173
3 isometric maximal lifting efforts with straight arms and legs.
Isometric lifting effort (iMLE), inspiratory and expiratory volumes, IAP.
Trained subjects had greater IAP. iMLE had an effect on %maxIAP and respiratory volume.
Kawabata, M.
2014 11
20-24 All M Healthy. avg 64.4 kg and avg 170 cm
3 dynamic submax lifting efforts with straight arms and legs.
iMLE, rate-IAP, peak-IAP, respiratory volume, timing of lift-off.
From 30-75% of iMLE, rate-IAP occurred early (P<0.01) and peak-IAP occurred late (P=0.12) relative to lift-off. Strong correlation between rate-IAP and peak-IAP (r=0.94-0.97). >60+ iMLE led to greater inspiratory volumes.
Lamberg, E.M.
2010 14
19-27 7 M 7 F No history of LBP.
avg 70.3 (15.8) kg and avg 172.8 (14) cm
4 self-paced "free-style" lifts of a standard milk crate.
Load, breathing method, inspiratory volume.
A uniform breathing method did not reveal itself. Frequency of inspiration was greatest before lift-off and highest inspiratory volume occurred at lift-off instead of before.
Lamberg, E.M.
2012 62
21-50 30 M 32 F 32 w/LBP and 30 w/no LBP (NLBP).
LBP avgs 69.6 kg/167.8 cm and NLBP avgs 75.1 kg/172.3 cm
Lowering of crate from table to floor 4 times w/crate empty and 4 times w/crate loaded at 25% of body weight.
Load, lung volume as % of vital capacity (VC).
Subjects w/LBP completed task with greater lung volume (45.9% VC) than subjects w/NLPB (40.9% VC). Increased age correlated with greater lung volumes. Increased load correlated with greater lung volumes.
Lepley, A.S.
2010 30
21.04-22.46
16 M 14 F Recreational exercise history.
avg 84.31 (19.2) kg and avg 180.26 (2.36) cm
Leg press and chest press machine exertions at estimated 1 rep max (3-6 reps).
Breathing method, blood pressure (BP), heart rate (HR).
Held breath technique had higher yet statistically insignificant (P<0.05) values for systolic BP (P=0.420), diastolic BP (P=0.531), and HR (P=0.713).
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MacDougall, J.D.
1985 5 22-28 All M Experienced bodybuilders.
NA Single-arm bicep curls, overhead presses, single and double-leg presses all to failure with Valsalva at various intensities.
Load, ITP, BP.
BP was significantly higher with concentric phase than with eccentric. Double-leg presses generated greatest BP with 480/350 in one subject. The Valsalva influenced a portion of observed pressure.
Marras, W.S.
1985 20
18-26 10 M 10 F Habitually active and regular exercise.
M avgs 73.8 kg and 179 cm F avgs 56.1 kg and 162.6 cm
Maximal force under isometric and isokinetic lifting conditions.
Torque, trunk angle, angular velocity, IAP.
Torque increased with greater trunk angles and decreased with greater angular velocities. IAP was a function of angle and weak indicator of torque.
McGill, S.M.
1987 3 27-32 All M Healthy with lifting experience.
75-81.5 kg and 172.5-180 cm
2 attempts of 3 dynamic lifting conditions at varying intensities and velocities.
Abdominal forces, IAP, compressive and shear forces on spine, EMG activity, load.
Low EMG activity for rectus abdominus and obliques during high loading phase of lifts. Prediction that compressive forces generated by abdominals were larger than the beneficial action of such forces.
McGill, S.M.
1990 6 24-29 NA 1 subject was an elite power lifter.
62.7-88.6 kg and 1.70-1.87 m
6 tasks (Valsalva, ab contraction, jump, sit ups, arm ergometry, squat lifts).
IAP, EMG activity, timing of EMG.
Most IAP was less than 100 mmHg for tasks other than Valsalva. Peak IAP occurred within 60 ms of onset of abdominal activation.
McGill, S.M.
1995 8 27.7 (4.1)
All M No history of LBP.
avg 87.8 (5.8) kg and 1.79 (0.04) m
Dynamic lifting and isometric holding of loads.
Load, tissue forces, EMG activity, IAP, ventilation rate, spine kinetics.
Greater loads led to stabilization by abdominals and lung airflow by the diaphragm. Low back demands and breathing challenges and high ventilation rates led to abdominal entrainment and low back compression in 6 subjects.
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Narloch, J.A.
1995 10
25-35 All M Athletic population.
NA 4 sets of isotonic leg presses under various breathing conditions and with different load intensities.
Load, breathing method, BP.
Mean BP at max with Valsalva was 311/284. Mean BP at max with slow exhalation was 198/175 (P<0.005).
Shirley, D. 2003 8 30-48 NA No history of LBP.
avg 76 (12) kg and 1.78 (0.06) m
Electrical force application of lumbar spine in a prone position.
IAP, EMG activity of spine, spine stiffness, respiratory patterns and volumes.
Stiffness of L2 and L4 increased above baseline with both inspiratory and expiratory efforts (greatest during expiration).
Strohl, K.P.
1981 4 26-34 All M Healthy. NA Physiological assessments during rest, breathing maneuvers, coughing, laughter, etc.
Breathing method, EMG activity.
Expulsive and Valsalva maneuvers generated same EMG activity. Phasic EMG activity during expiration was greater in upper abdomen.
Discussion
Before addressing any possible correlations between spine stability and force
production, the key variables involved in developing stability must be identified,
examined, and positioned in a chronology that demonstrates causality. There has been
much debate in the literature surrounding the cause(s) of increased spine stability, with
some researchers promoting IAP as the sole instigator of stabilization, and other scientists
claiming that a combination of raised IAP and co-contraction of trunk musculature leads
to such an outcome (Hagins et al. 2004). According to Cholewicki et al. 2002, it is
impossible to have co-contraction of the trunk musculature without developing IAP and
ITP, yet it is also unfeasible to generate IAP without co-contraction of the trunk muscles
and elevation of ITP. They concluded that when lifting a heavy object, all of the trunk
musculature co-contracts to a certain extent, IAP and ITP both elevate, and the
compression and stability of the spine increase. Furthermore, they asserted that this
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combination of trunk muscle co-activation and increased IAP has a significant and
positive effect on the biomechanics involved in weightlifting tasks.
IAP is generated by a series of physiological events in the body, the first and
foremost being respiration. During inhalation, the diaphragm lowers as the volume in the
thoracic cavity increases (raised ITP). Co-contraction of the abdominal musculature
causes an upward force to press against the descended diaphragm, which if held in place
can lead to an increase in IAP. Additionally, closing of the glottis, as during either the
Valsalva maneuver or the held breath technique (no forced exhalation), assists in
maintaining ITP by preventing air in the thoracic cavity from escaping. Therefore,
closing the glottis can passively assist the diaphragm in increasing IAP (Hagins et al.
2004). In a study that analyzed the relationship between respiratory patterns and IAP
levels during lifting, the breathing style that achieved the highest IAP readings was
maximum inhalation prior to lift-off and held breath during/post lift-off. The authors
referred to this breathing pattern as the “held breath technique,” which is similar to the
Valsalva maneuver, minus the forced exhalation against a closed glottis (Hagins et al.
2004).
*Data from a study by Hagins et al. 2004, which shows a clear difference between the magnitude of IAP attained during the inhalation-hold breathing condition in comparison to all other breathing patterns used. In addition, the larger loads led to significantly greater IAP values than the smaller loads.
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The volume of inspired air (Vi), in addition to its containment (as just described),
plays a significant role in the development of IAP. Some researchers suggest that there is
a connection between the magnitude of load and inspiratory volume. In a study focusing
on this exact relationship, Lamberg et al. 2010 hypothesized that a standardized form of
breathing reveals itself during lifts of maximally tolerated loads, thereby insinuating that
greater mechanical challenges produce a more consistent type of breath control during
weightlifting as a means of improving lumbar spine stability. The authors theorized that
inspiratory rate and volume would increase rapidly right before lift-off and that breath
holding would occur during and after lift-off, thus raising IAP levels and increasing
lumbar spine stability via pressurization. The results of this study showed that inspiratory
volume was noticeably higher during lifts of maximal loads versus lifts of minimal or
moderate loads. Additionally, volume did not differ significantly between lifts of
moderate and minimal loads, suggesting a possible threshold by which intensity sparks a
change in the coordination of the motor and respiratory pathways. Across all load
intensities, inspiration occurred rapidly prior to lift-off, while either exhalation or held
breath dominated the post-lift phase. The authors noted that the lifting of maximally
tolerated loads did not lead to a uniform breathing pattern at or post lift-off. However,
they did find a trend of greater occurrences of breath holding during and after lift-off of
*Data from a study by Lamberg et al. 2010, which shows that inspiratory volumes were significantly greater with maximally tolerated loads than with moderately or minimally tolerated loads.
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maximally tolerated loads, which did achieve statistical significance. These findings
support a previous study by Hagins et al. 2005 that showed increases in both frequency
and volume of inspiration during the pre-lift period. The greater the load (heavy and
medium weights) the more frequent breath holding occurred at/post lift-off. In addition,
subjects tended to hold their breath more consistently when managing heavier loads.
Shirley et al. (2003) found increases in lumbar stiffness when lung volumes were
greater than tidal volume (Vt). In this study, the authors found inspired volumes to be
greater than tidal volume (500 mL) across all load intensities (minimal 650 mL, moderate
819 mL, and maximal 1143 mL). The findings from both of these studies suggest that
enhancing the amount of inspired air prior to lift-off is a consistent pattern of breath
control during weightlifting, across all load types (with a trend of greater volumes with
greater load intensities). The influence of motor control on breathing appears to be
optimized for the greatest compressive and shear forces, which exist during the first 0.2-
0.4 seconds of a lift (Gagnon et al. 1991).
When considering client programming, personal trainers are continuously
reminded to promote exercises that are both effective and safe. In regards to IAP, many
exercise physiologists consider the Valsalva maneuver to be contraindicated due to the
immense strain that it places on the cardiovascular system (Narloch et al. 1995). Lepley
et al. 2010 hypothesized that employment of a held breath technique during chest and leg
pressing would result in similarly dangerous blood pressure levels as the Valsalva
maneuver. Their study, however, showed that although breath holding led to a slight
increase in blood pressure (systolic 157.9/diastolic 93.1), this increase was not
significantly greater than the blood pressure achieved via controlled breathing (systolic
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142.4/diastolic 88.2). These data reinforce that the held breath technique is not only an
effective method of developing IAP, it is a safe breathing pattern for weightlifting
exercise.
In accordance with the notion that co-activation of trunk musculature aids IAP in
improving spine stability, Cresswell et al. 1992 conducted a study focusing on the
interaction between IAP and the abdomen, in which they inserted bilateral intra-muscular
electrodes and monitored the muscular activity using ultrasound equipment. The primary
focus was myoelectric activity of the transversus abdominus, both on its own and in
relation to potential activation of the other three main abdominals (internal oblique,
external oblique, and rectus abdominus) during maximal isometric loading of the trunk.
The authors found the transversus abdominus to be the main contributing factor, along
with potential co-activation of the diaphragm, in the development of IAP during trunk
extension activity. However, in terms of voluntary pressurization during events such as
the Valsalva maneuver, they concluded that coordination between all four abdominal
muscles causes an increase in IAP.
*Data from a study by Cresswell et al. 1992, which shows the differences in the myoelectric activity of the four main abdominal muscles. Both figures indicate a greater contribution by the transversus abdominus during maximal trunk extension and Valsalva maneuvers.
16
The transversus abdominus plays an important role in IAP development; however,
there have also been documented increases in the electromyographic activities of the
other abdominals, as well as the erector spinae and latissimus dorsi muscles, in
connection with elevated IAP levels during isometric trunk loading (Cholewicki et al.
1999). The coordination of these six key trunk muscles increases both the stiffness of the
torso and the overall stability of the lumbar spine. In a 1999 study, Cholewicki et al.
found that during preparation for high-intensity physical actions such as lifting,
contraction of the abdomen and back musculature stiffened both the lumbar spine and the
thoracic cage (thoracic vertebrae and ribcage). This finding has functional significance in
regards to weightlifting since numerous trunk and upper limb muscles originate from the
thorax. The rigidity of this region therefore plays an important role in supporting the
actions of the joints and musculature used during upper body weightlifting. Additionally,
the authors assert that a greater mechanical advantage for the abdominal wall muscles,
particularly the transversus abdominus and obliques, can be attained when they contract
around a pressurized abdominal cavity, which supports the notion that raised IAP offers
biomechanical benefits during lifting.
Evidence from these and several other studies helps to develop causal links
between breathing patterns, IAP levels, trunk muscle activity, and spine stability. The
held breath technique described earlier in this review appears to be the most safe and
effective respiratory pattern for weightlifting tasks. Although the bonds between these
variables have been identified and substantiated, there remains a shortage of data
connecting them to force production. One central study focusing on potential
correlations between breathing patterns, IAP, and force production was conducted by
17
Hagins et al. 2006. The authors used a single independent variable, breathing pattern, to
influence two outcome variables, IAP level and force production, during a maximal
isometric trunk extension effort in a knee bent posture. The three types of breathing
patterns employed in this study were maximum inhalation prior to lift-off combined with
breath holding (held breath technique), maximum exhalation prior to lift-off combined
with breath holding, and maximum inhalation prior to lift-off combined with steady
exhalation during the exertion phase. The effects of breathing style on maximum force
production were low (P = 0.089); however, the results suggest some differences in the
magnitude of force between the various breath conditions (~4kg).
The authors argued that although such a small difference may not have vast
significance in the general population, it could potentially have functional relevance in
elite weightlifting populations. In addition, the authors mentioned several cautions
regarding both the design and real world applicability of their experiment. Due to the
invasive nature of IAP measurement (via a nasogastric tube), only eleven of the thirty-
three subjects were monitored for IAP. The lack of concrete data regarding IAP on two-
#Diagrams and data from a study by Hagins et al. 2006. The diagram illustrates the physical parameters of the experiment. The data shows that although inhalation-hold breathing led to the greatest IAP value, it also resulted in the lowest magnitude of force production.
18
thirds of the subject population weakens the conclusions drawn by this study. As for the
physical parameters of the experiment, the employment of an isometric trunk exertion,
rather than a dynamic lifting task, reduces the significance of these findings in real world
weightlifting settings. At the end of their study, the authors explicitly stated, “Future
research should use methods which examine more functional dynamic lifting tasks in
order to determine if there is a link between breath control, IAP, and force production.”
(Hagins et al. 2006, page 779)
Conclusion
There is a wealth of data from the past three decades connecting breathing
patterns, IAP, and spine stability, with the held breath technique consistently championed
as the most safe and effective method of developing both IAP and spine stability. Co-
contraction of key trunk muscles (the transversus abdominus, external and internal
obliques, rectus abdominus, erector spinae, and latissimus dorsi) aids significantly in
elevating IAP values. There is, however, a lack of research focusing on the relationship
between IAP, spine stability, and force production. Of the studies that do examine this
association, several design flaws (mainly the employment of an isometric exertion and
the lack of data regarding IAP) undermine the applicability of the conclusions. Appendix
A* contains a list of key recommendations for future studies, many of which focus on the
design and physical testing elements of experimentation.
*Appendix A
1) Ensure that every subject is measured for IAP (either using a nasogastric or rectal
pressure transducer), EMG activity (on key areas of the trunk), and force production (via
a force transducer and load cell).
19
2) Test subjects using dynamic lifts rather than isometric lifts. Several studies
mentioned both velocity and trunk angle as key variables, and so dynamic movements
may produce vastly different results.
3) If using dynamic lifts, test the subjects on several primary multi-joint
weightlifting exercises (bench press, deadlift, lat pull down, overhead press, seated row,
and back squat) to better reflect a typical personal training environment.
4) It is possible that increased IAP and spine stability may only assist force
production during certain set/rep schemes. The majority of the research has utilized one
repetition (with multiple attempts); however, most individuals (including athletes)
execute several repetitions during weightlifting exercise. Future studies might benefit
from dividing subjects by set/rep categories for power, strength, hypertrophy, and
muscular endurance.
References
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