musculoskeletal health in women: impact of stress, aging ......aging “normal” aging •loss of...

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Musculoskeletal Health in Women: Impact of Stress, Aging,

and PregnancyRita Deering, DPT, PhD candidate

Clinical & Translational Rehabilitation Health Sciences PhD Program

Department of Physical Therapy

Marquette University

Presentation Overview

• History & Definitions

• Sex Differences in Muscle Function• Impact of stress on sex differences

• Impact of Aging on sex differences

• Discussion of Clinical Importance

• Pregnancy & Postpartum• Physiological Changes

• Common PT related issues

• Clinical Assessment of pregnancy related PGP

• Abdominal Muscle Function & Pain Perception after Pregnancy


History

• Women have historically been excluded from clinical research due to “greater biological complexity”

• Many health care findings from research conducted on men have been generalized to be applicable to women

• 1990: NIH established a policy stating that women should “commonly” be part of medical and behavioral research

• 2012: The journal Endocrinology mandated that methods sections must disclose the sex of subjects studied (whether human, animal or cell cultures) (Blaustein Endocrinology, June 2012, 153(6):2539–2540)

• 2015: NIH issued the announcement “Consideration of Sex as a Biological Variable in NIH-funded Research”

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“Sex” vs. “Gender”

• Sex: biological differences (reproductive organs, chromosomes)

• Gender: a “complex psychological, environmental, sociocultural,

and political framework that encompasses the characteristics ascribed to each sex that are generally accepted and influenced by society.” (M. Racine et al 2012)

www.thewrap.comwww.museumofplay.org

Skeletal Muscle Strength

Force

• Voluntary activation: ability of the

nervous system to drive the muscle

• Muscle cross-sectional area: number

of muscle fibers and sarcomeres in

parallel

Maximal strength

Slide courtesy of Dr. Sandra Hunter, PhD

Muscle Strength and Fatigue

An acute, exercise-induced reduction in the force or

power of a muscle (Gandevia, 2001; Enoka and Duchateau 2008).

Force

100 %

Before After

Fatiguing

Exercise

Decline

Maximal

Force


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Muscle Function: Muscle Function: Muscle Function: Muscle Function: Strength, Fatigability and Steadiness

-5.0

3

2

1

0

volt

V-F

orc

e

1

20 30 40 50 60 70 80 90100110120130140150160170180190200210220230240250260270280290300310320330340350360

s60 s

50% MVC

force

Time to Task Failure

Maximal strength

• Strength

• Muscle Fatigue: reduction in strength and time to task

failure

• Steadiness: force fluctuationsSlide courtesy of Dr. Sandra Hunter, PhD

Subje

ct

Num

bers

0

500

1000

1500

2000

2500

3000

Men Women

Muscle Fatigue Studies

78 studies (as of

April 2014)

Disproportionate testing of men compared with women or the

under-reporting of sex effects can mask an understanding of

relevant sex differences in fatigability and performance.

Sex Differences in Research of Muscle Function and Fatigability












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Sex Differences in Skeletal Muscle Function

www.si.com

Muscle Mass & Strength

• Men have more muscle mass than women, thus are usually stronger

• When strength is normalized to muscle mass, the sex difference in strength is negligible

• Greater muscle mass and higher force levels are usually associated with greater fatigability during sustained isometric contractions

• Greater compressive force generated by larger muscle mass can impair muscle perfusion and clearance of metabolic byproducts

Hunter SK Acta Physiologica 2014

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Force (% Max)

10 20 30 40 50 60 70 80 90 100

Se

x D

iffe

rence

in F

atigue (

%)

-40

-20

0

20

40

60

80

Adductor Pollicis

Finger Flexors

Elbow Flexors

Elbow Extensors

Neck Muscles

Back Extensors

Knee Extensors

Ankle Dorsiflexors

Women more fatigue resistant than men

>55 studies

Static Contractions


Sex Differences in Fatigability Sex Differences in Fatigability Sex Differences in Fatigability Sex Differences in Fatigability


Time to Task Failure

Men: 819 + 306 s

Women: 864 + 391 s

P>0.05

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Trunk Flexor MVC StrengthUpright Sitting

Women Men

MV

C T

orq

ue

(N

m)

0

10

20

30

40

50

60

70

Trunk Flexor FatigabilityIntermittent Isometric Submaximal Fatiguing Protocol

Women Men

Tim

e to

Ta

sk F

ailu

re (

s)

0

200

400

600

800

1000

Association Between Trunk Flexor Strength and Trunk Flexor Fatigability

Time to Task Failure (s)

0 200 400 600 800 1000 1200 1400 1600 1800

MV

C S

treng

th (

Nm

)

20

40

60

80

100

120 Women

Men

Impact of Stress on Fatigability

Keller-Ross et al 2014

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Impact of Stress on Control of Force

Pereira et al 2015

Sex Differences in Muscular Response to Unloading

• Women have greater loss of total volume of muscle and fiber area, especially for type II fibers.

• For 30 days of unloading, women demonstrate more significant decline in strength as compared to men.

• With short term unloading, women show more dysfunction in neural activation.

• Women may require greater recovery time than men following unloading.

Ploutz-Snyder et al 2014

Summary of Sex Differences

• Women are often weaker and less fatigable

• Results are task- and muscle-dependent!

• Women show greater decline in time to task failure with cognitive stress

• Women demonstrate greater deterioration of control of force with cognitive stress

• Women are more susceptible to disuse impairments (atrophy, neural activation deficits) and require greater recovery time

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Possible Mechanisms forSex Differences


Contractile Properties

• Women have slower muscle

• Women tend to have more Type I muscle fibers than men

• Women have slower SR Ca2+ kinetics

• ATPase activity

• Uptake into SR


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Muscle Metabolism

• High force isometric contractions: men demo greater glycolysis

• High intensity sprint exercise: women have lower accumulation of lactate, greater preservation of ATP

• Moderate/high intensity exercise (whole body): women oxidize more fat and less CHO

• Muscle liproprotein lipase, membrane fatty acid transport protein-1, FAT/CD36 protein, and citrate synthase levels are higher in women

• Not dependent on level of training or age

• Capacity for fat metabolism is associated with estrogen


Sex Hormones

• Conflicting evidence regarding influence of menstrual cycle on skeletal muscle performance

• Strength and fatigability of isometric contractions do not appear to be altered by day of menstrual cycle

• Birth control/menstrual cycle can impact metabolism, to a small degree, during long duration exercise

• Impact is more profound when climate is hot/humid


CNS Function

• Women demonstrate higher activation of the cortex (IL & B) during finger tapping or when preparing to reach, while men demonstrate higher activity in subcortical areas (ex: basal ganglia)


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Aging

“Normal” Aging• Loss of muscle mass

• Selective atrophy of Type II fibers

• Loss of alpha motor neurons

• Collateral sprouting

• Instability of neuromuscular junction

• Infiltrated by fat and fibrotic tissue

• More susceptible to negative effects of inflammation (Gheller et al 2016)

• Greater variability in motor performance

• Decreased strength and power

• Altered fatigability

• <75 years old typically LESS fatigable for isometric contractions

• >75 years old typically MORE fatigable for isometric contractions

• Old and very old MORE fatigable with high velocity dynamic contractionsHunter, Pereira, Keenan 2016

Ke

nt-B

rau

n &

Ng

19

99

Hunter, Pereira, Keenan 2016

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Sex Differences with Age• Women lose skeletal muscle mass at a slower rate than men (Gheller et al 2016)

• Women have 2.5x more fatty infiltrate in quads (Forsberg et al 1991)

• Women have lesser loss of strength than men (~50%) (Gheller et al 2016)

• Likely due to men having greater strength than women

• Old women have less loss of strength during eccentric muscle activations than old men.

• Function of “slower cross-bridge kinetics, an increased proportion of weakly-bound compared with strongly-bound cross-bridges, and a stiffer musculotendinous complex” (Hunter, Pereira, Keenan 2016)

• Old women demonstrate greater fatigability with both low and high cognitive demand (Pereira 2015)

• Mechanisms not fully understood at this time

Pereira 2015

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Discussion

• Why is fatigability important?

• Why are sex differences important?

• Clinical implications of impact of stress on performance?

• Clinical implications of impact of aging on performance?

• Other clinical insights from the group?

www.hulu.com

References• Blaustein JD. Animals Have a Sex, and so Should Titles and Methods Sections of Articles in Endocrinology. Endocrinology 2012; June, 153(6): 2539-2540.

• Racine et al. A Systematic Literature Review of 10 Years of Research on Sex/Gender and Experimental Pain Perception: Parts 1 & 2. Pain 2012. 153: 602-618, 619-635.

• Hunter SK. Sex differences in human fatigability: mechanisms and insight to physiological responses. Acta Physiologica 2014; 210: 768-789.

• Hunter et al. Fatigability of the elbow flexor muscles for a sustained submaximal contraction is similar in men and women matched for strength. J ApplPhysiol 2004; 96: 195-202.

• Hunter et al. Men are more fatigable than strength-matched women when performing intermittent submaximal contractions. J Appl Physiol 2004; 96: 2125-2132

• Keller-Ross et al. Stressor-induced increase in muscle fatigability of young men and women is predicted by strength but not voluntary activation. J ApplPhysiol 2014; 116: 767-778.

• Pereira et al. Age and sex differences in steadiness of elbow flexor muscles with imposed cognitive demand. Eur J Appl Physiol 2015; 115(6): 1367-1379.

• Ploutz-Snyder et al. Effects of sex and gender on adaptation to space: musculoskeletal health. J Womens Health 2014; 23(11): 963-6.

• Hunter SK, Pereira HM, Keenan KG. The Aging Neuromuscular System and Motor Performance. J Appl Physiol 2016; August; doi: 10.1152/japplphsiol.00475.2016 [epub ahead of print]

• Kent-Braun JA & Ng AV. Specific strength and voluntary muscle activation in young and elderly women and men. J Appl Physiol 1999; 87(1): 22-9.

• Gheller et al. Understanding Age-related changes in skeletal muscle metabolism: Differences between males and females. Annu Rev Nutr 2016; 36: 129-56.

• Forsberg et al. Muscle composition in relation to age and sex. Clin Sci 1991; 81: 249-56.

• Pereira et al. Sex differences in arm muscle fatigability with cognitive demand in older adults. Clin Orthop Relat Res 2015; 473: 2568-2577.











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Pregnancy & Postpartum

http://www.xsight.com.au

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Hormonal Changes

• Estrogens

• Levels increase

• Estradiol, estrone, estriol

• Facilitate growth of the uterine muscle

• Cause the ligaments of the pelvis and the pubic symphysis to become softer and more lax

• Contribute to growth of milk ducts

• Boost release of prolactin from mother’s pituitary gland

• Increases creation of progesterone

Chearskul 2006

Hormonal Changes

• Progesterone

• Increases

• Necessary for implantation and successful maintenance of pregnancy

• Maintains lining of the uterus and facilitates production of nutrients to sustain zygote early in pregnancy

• Triggers production of prolactin

• Used by fetal adrenal gland to produce cortisol and aldosterone

• Decreases uterine muscle excitability

• Increases mother’s respiratory rate to offset increased CO2 produced by heightened metabolic demand

Chearskul 2006

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Hormonal Changes

• Relaxin

• Increases

• “decreases uterine muscle contractility by reducing the activity of uterine myosin kinase”

• Softens the cervix and causes pelvic joint laxity

• Boosts activity of collagenase enzyme

• May also have renal effects

• “renal vasodilation, hyperfiltration, and reduced myogenic activity of small renal arteries”

Chearskul 2006

Hormonal Changes• Insulin

• 1st half of pregnancy: Mom has greater sensitivity to insulin

• 2nd half of pregnancy: Mom is in state of insulin resistance• Shift to fat metabolism for Mom

• More plasma glucose and AA which facilitates uptake by the placenta to fetus

• Estrogens, progesterone, placental growth hormone, and cortisol also influence insulin resistance

• Gestational Diabetes occurs in ~4% of pregnancies

• Prolactin• Progressive increase throughout pregnancy

• Regulates fat metabolism

• Renin Angiotensin System• Increased Na+ retention

• Contributing factor to development of preeclampsiaChearskul 2006

Hormonal Changes

• Elevated cortisol

• Facilitates fat storage in Mom

• Stimulates development of mammary glands

• Increased thyroid hormones and ACTH from pituitary

Chearskul 2006

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Stretch of the Abdominal Wall

• Growing fetus=growing uterus=abdominal wall expansion

• Hypertrophy of type I fibers & increased proportion of type I fibers shown in animal studies (Lalatta Costerbosa et al 1988)

Physical Activity

• ACOG guidelines

• Advocate the CDC recommendation of “150 minutes of moderate-intensity aerobic activity every week”.

• Contraindications to exercise

• “certain types of heart and lung diseases”

• Incompetent cervix

• Multiple gestation

• Risk factors for preterm labor

• Placenta previa (after 26 weeks)

• Preterm labor/rupture of membranes

• Preeclampsia

• Severe anemia

• Benefits of Exercise

• Decreased back pain

• Combats constipation

• “may decrease risk of gestational diabetes, preeclampsia, and cesarean delivery”

• Maintain healthy weight

• General cardiovascular benefits

• “helps you lose the baby weight after your baby is born”

• Advocate continued exercise after delivery to decrease risk of DVT and to manage weight

http://www.acog.org/Patients/FAQs/Exercise-During-Pregnancy

The Physical Activity Problem

• 68% of pregnant women report decreased physical activity

• 80% of postpartum women report significant decline in physical activity level

(Gutke 2011)

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Big Picture Impact on the Musculoskeletal System

• Ligamentous laxity• Pelvis

• Wrists

• Decreased fascial integrity• DRA

• Impaired force transfer• Brown & McGill study

• Increased fatigability?• Gracovetsky 2008

• Fiber type shift?• Animal studies

Definition of Pelvic Girdle Pain• Location: between posterior iliac crest and gluteal fold

• SIJ

• Pubic symphysis

• Posterior thigh

• Symptoms: decreased tolerance of sitting, standing, walking

• Confirmed by:• Ruling out lumbar spine as pain generator

• Reproduction of symptoms with the following tests:• Posterior Pelvic Pain Provocation test (P4)

• Patrick’s FABER

• Palpation of long dorsal ligament

• Gaenslens Test

• Modified Trendelenburg Test

• Palpation of pubic symphysis

• Active Straight Leg Raise (ASLR) Test

Vleeming 2008

Prevalence & Impact of PGP

• Prevalence in pregnant women: 20-23% (Albert 2000)

• 50-75% if include LBP (Wu 2004, Wang 2004, Kristiansson 1996)

• Long term concerns:

• 25% of pregnant women with PGP will continue to have pain in the postpartum period (Ostgaard et al 1996, Albert et al 2001, Wu et al 2004)

• 20% of women will avoid a future pregnancy due to severe PGP (Brynhildsen1998)

• Worldwide, 1 in 4 women have chronic pelvic pain (Nygaard et al 2008)

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Clinical Assessment of PGP in Pregnancy

• Posterior Pelvic Pain Provocation test (P4)

• Patrick’s FABER

• Palpation of long dorsal ligament

• Gaenslens Test

• Modified Trendelenburg Test

• Palpation of pubic symphysis

• Active Straight Leg Raise (ASLR) Test

Posterior Pelvic Pain Provocation (P4)Posterior Pelvic Pain Provocation (P4)Posterior Pelvic Pain Provocation (P4)Posterior Pelvic Pain Provocation (P4)• Patient supine on plinth

• Hip flexed to 90 degrees, knee relaxed

• Stabilize CL pelvis

• Downward pressure through long axis of femur

• Positive test: reproduction/exacerbation of posterior pelvic pain

• 0= no pain

• 1 (mild) = complaint of pain without physical manifestation of pain

• 2 (moderate) = complaint of pain with physical manifestation of pain

• 3 (unbearable)= unable to complete test due to patient withdrawal

Ostgaard et al 1994

Patrick’s FABERPatrick’s FABERPatrick’s FABERPatrick’s FABER

• Patient supine on plinth

• Leg brought into Flexion, ABduction, External Rotation

• Gentle overpressure applied at end-range (“forced FABER”)

• Positive Test: reproduction/exacerbation of posterior pelvic pain (SIJ) or pubic symphysis

Albert et al 2000

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Palpation of long dorsal SIJ ligamentPalpation of long dorsal SIJ ligamentPalpation of long dorsal SIJ ligamentPalpation of long dorsal SIJ ligament

• Patient in sidelying with slight hip and knee flexion

• Position in prone for postpartum women

• Palpate along length of the ligament

• Positive test: Provocation/exacerbation of pain

• 0= no pain

• 1 (mild) = complaint of pain without physical manifestation of pain

• 2 (moderate) = complaint of pain with physical manifestation of pain

• 3 (unbearable)= unable to complete test due to patient withdrawal

Albert et al 2000

GaenslensGaenslensGaenslensGaenslens TestTestTestTest

• Two options for positioning (modify for pregnancy)

• One leg in flexion, CL leg brought into extension, mild overpressure on both legs

• Positive test: reproduction/exacerbation of posterior pelvic pain (especially SIJ) on side of extended leg

www.clinicalgate.com

Vleeming et al 2008

Laslett et al 2005

Laslett 2008

Modified Trendelenburg TestModified Trendelenburg TestModified Trendelenburg TestModified Trendelenburg Test

• Patient in standing

• PT stands behind patient

• One leg brought into flexion

• Positive test: pain in pubic symphysis.

• Drop of pelvis CL to stance leg (functional hip weakness)

Albert et al 2000

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Palpation of Pubic SymphysisPalpation of Pubic SymphysisPalpation of Pubic SymphysisPalpation of Pubic Symphysis

• Patient can be in supine, semi-reclined, sidelying

• Clinician palpates pubic symphysis

• Positive test: Reproduction/exacerbation of pain at pubic symphysis

Albert et al 2000

Active Straight Leg Raise (ASLR) Test

• Patient supine on plinth with legs extended

• Raise one leg at a time (heel height of 20 cm)

• Patient rates difficulty• 0= not difficult at all• 1= minimal difficulty• 2= somewhat difficult• 3= fairly difficult• 4= very difficult• 5= unable to lift leg off plinth

• If difficulty is rated above a zero, therapist provides manual compression to the pelvis and the test is repeated

• Positive Test: Decrease in reported difficulty with manual pelvic compression

www.dianelee.ca

Mens 2012

Treatment

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Switching Gears: Research Presentation

Abdominal Muscle Function in Postpartum Women

Rita Deering, DPT, PhDc

Doctoral Candidate, Clinical & Translational Rehabilitation Health Science Program, Department of Physical Therapy, Marquette

University

http

://ww

w.xsig

ht.co

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The Abdominal Muscles Are EssentialThe Abdominal Muscles Are EssentialThe Abdominal Muscles Are EssentialThe Abdominal Muscles Are Essential

• Synergists of Pelvic Floor Muscles

• Assist with breathing

• Regulate Intra-Abdominal Pressure

• Essential for lumbopelvic stability

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“The Core”

� Middle of the kinetic chain

� Link between the upper and lower extremities

� Transfer of energy from upper to lower extremities (Kibbler 1998)

Labor and Delivery: Core Disruption

(Ashton-Miller 2009)

Vaginal delivery

Cesarean delivery

Traditional Postpartum Visit in the USTraditional Postpartum Visit in the USTraditional Postpartum Visit in the USTraditional Postpartum Visit in the US

• Pelvic Exam

• Assessment of uterine involution

• Assessment of soft tissue healing

• Perineum

• Surgical site

• Pap Smear

• Discussion regarding birth control

6 Weeks Postpartum6 Weeks Postpartum6 Weeks Postpartum6 Weeks Postpartum

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• Abdominal dysfunction has not been well quantified• Not much research on effects of pregnancy has been done on human subjects

• Strength/force testing that has been done on humans is not very objective

• Most abundant abdominal muscle research focuses on presence and degree of Diastasis Recti Abdominis (DRA)

“Common” is often dismissed as “normal”

• Does function of the abdominal muscles change after pregnancy?

• Force production

• Trunk flexion

• Torque-Angle Curve

• Fatigability

Research QuestionsResearch QuestionsResearch QuestionsResearch Questions

• What factors contribute to function of the abdominal muscles after pregnancy?

• Mode of delivery

• DRA

• Activity level

• Pain

• Body composition

• Muscle thickness

• Muscle activation

• Time since delivery

Research QuestionsResearch QuestionsResearch QuestionsResearch Questions

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Hypotheses

• In comparison to controls, postpartum women will:

• Demonstrate decreased strength during a maximal voluntary isometric trunk flexion contraction

• Be more fatigable, as evidenced by a shorter time to task failure

• Have thinner rectus abdominis muscles

• Report decreased physical activity

• Over the course of 16 weeks:

• Postpartum women will demonstrate an improvement in strength and fatigability, but will remain weaker and more fatigable than control women

Final Test

Sessions

(24-26 wks

postpartum)

Protocol: Laboratory Measures of Strength and Fatigability

MVC

60

sec

50% MVC

target line

(16.4 Nm)

To

rqu

e

MVCMVC

Protocol: Clinical Measures of Strength and Fatigability

http://classconnection.s3.amazonaws.com/385/flashcards/1258385/png/trunk_flexion1330632161223.png

http://2.bp.blogspot.com/-Vo1_sKLqWZ0/UYQIkN2lBfI/AAAAAAAAAIQ/Rdz_SLPhVhA/s1600/5030J1+Jamar+Hydraulic+Hand+Dynamometer.jpg

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Protocol: Laboratory Measure of Muscle Thickness

RESULTSRESULTSRESULTSRESULTS

Initial Time Point (8-10 weeks postpartum): 15 Control (25.3 + 5.2 years), 29

Postpartum (31.4 + 5.2 years) women

Follow Up Time Point (24-26 weeks postpartum): 14 Control (25.4 + 5.8 years), 28

Postpartum (32.0 + 5.1 years) women

Postpartum Women (8-10 Weeks PP): 18 vaginal delivery, 11 Cesarean Delivery

Postpartum Women (24-26 Weeks PP): 17 vaginal delivery, 11 Cesarean Delivery

Body Composition

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Visceral Adipose Tissue

Postpartum Control

Volu

me

(in

3)

0

10

20

30

40

50


Postpartum Control

Ma

ss (

lb)

0.0

0.2

0.4

0.6

0.8

1.0

1.2

1.4

1.6

****


Postpartum Control

Ma

ss (

lb)

0.0

0.2

0.4

0.6

0.8

1.0

1.2

1.4

1.6


Postpartum Control

Vo

lum

e (

in3)

0

10

20

30

40

50

INITIAL

FOLLOW

UP

*

*

Thickness of Right Rectus Abdominis Muscle Belly

Position Relative to Umbilicus

2.5 cm Above 2.5 cm Below

Thic

kness (

cm

)

0.0

0.2

0.4

0.6

0.8

1.0

1.2 Postpartum

Control

***

Thickness of Right Rectus Abdominis Muscle Belly

Position Relative to Umbilicus

2.5 cm Above 2.5 cm Below

Thic

kne

ss (

cm

)

0.0

0.2

0.4

0.6

0.8

1.0

1.2 Postpartum

Control

**

Physical Activity

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Quantification of Moderate Physical Activity

ActiGraph

Postpartum Control

Ave

rage

min

ute

s/d

ay

0

10

20

30

40

50

60

Physical Activity Quantification

ActiGraph

Postpartum Control

Ave

rage

ste

ps/d

ay

0

2000

4000

6000

8000

10000

12000

**

Physical Activity QuantificationActiGraph

Postpartum Control

Ave

rage

ste

ps/d

ay

0

2000

4000

6000

8000

10000

Quantification of Moderate Physical ActivityActiGraph

Postpartum Control

Avera

ge m

inu

tes/d

ay

0

10

20

30

40

*

INITIAL

FOLLOW

UP

Self-Reported Physical Activity

Over the Last 12 Months

Postpartum Control

ME

T h

ours

/we

ek

0

10

20

30

40

50

60

*

Self-Reported Physical ActivityOver the Last 12 Months

Postpartum Control

ME

T h

ou

rs/w

ee

k

0

10

20

30

40

50

*

INITIAL FOLLOW UP

Inter-Recti Distance

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Inter-Recti DistanceMeasured with Ultrasound

Position (relative to umbilicus)

4 cm above

2.5 cm above

2.5 cm below4 cm below

Dis

tance

(cm

)

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

Control

Postpartum

INITIAL

Control n=16, Postpartum n=19

Position p<0.001

Position x Group p=0.025

Group p<0.001

FOLLOW UP


Position p<0.001


Group p<0.001

Inter-Recti DistanceMeasured with Ultrasound

Position (relative to umbilicus)

4 cm above

2.5 cm above

2.5 cm below4 cm below

Dis

tance (

cm

)

0.0

0.5

1.0

1.5

2.0

2.5

3.0

Control

Postpartum

Pain Testing

Pressure Pain Threshold

Nailbed of Left Middle Finger

Postpartum Control

Thre

sho

ld (

KP

a)

0

50

100

150

200

250

300

350


Lower Abdomen

(Site of Pfannenstiel Incision)

Postpartum Control

Thre

sho

ld (

KP

a)

0

50

100

150

200

250

***

Pressure Pain ThresholdLower Abdomen

(Site of Pfannenstiel Incision)

Postpartum Control

Thre

sho

ld (

KP

a)

0

50

100

150

200

250


Nailbed of Left Middle Finger

Postpartum Control

Thre

sho

ld (

KP

a)

0

50

100

150

200

250

300

**

INITIAL

FOLLOW

UP

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Change in Pressure Pain Threshold From Before to After Exercise

Upper Abdominal Site

PreEx PostEx

Pre

ssure

Pa

in T

hre

sho

ld (

KP

a)

100

120

140

160

180

200

220

240

260

Control

Postpartum

INITIAL


Time p=0.001

Time x Group p=0.195

Group p=0.005

Change in Pressure Pain Threshold From Before to After ExerciseUpper Abdominal Site

PreEx PostEx

Pre

ssure

Pain

Thre

shold

(K

Pa)

80

100

120

140

160

180

200

220

Control

Postpartum

FOLLOW UP


Time p=0.003


Group p=0.018

Functional Tests

Six Minute Walk Test Performance

Postpartum Control

Dis

tance (

m)

0

200

400

600

800

*

Six Minute Walk Test Performance

Postpartum Control

Dis

tance

(m

)

0

200

400

600

800

INITIAL FOLLOW UP

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Strength

Hand Grip Strength

Right Left

Grip S

trength

(lb

s)

0

20

40

60

80

100Postpartum

Control

Hand Grip Strength

Right Left

Gri

p S

trength

(lb

s)

0

20

40

60

80

100Postpartum

Control

INITIAL

FOLLOW UP

Trunk Flexor Strength

Maximum Voluntary Isometric Contraction

Pre-Fatiguing Exercise

Postpartum Control

Torq

ue (

Nm

)

0

10

20

30

40

50

60

Manual Muscle Testing Strength Grade

1 2

Str

ength

Gra

de

0

1

2

3

4

5

Postpartum Control

*

**

Trunk Flexor StrengthMaximum Voluntary Isometric Contraction

Pre-Fatiguing Exercise

Postpartum Control

Torq

ue (

Nm

)

0

10

20

30

40

50

60

Manual Muscle Testing Strength Grade

1 2

Strength

Gra

de

0

1

2

3

4

5

Postpartum Control

**

INITIAL

FOLLOW

UP

9/19/2016

31

Torque Angle Curve

Torque-Angle Curve of the

Trunk Flexor Muscles

Position (degrees)

-50 -40 -30 -20 -10 0 10 20 30

Torq

ue (

Nm

)

0

20

40

60

80

100

Postpartum

Control

INITIAL


Position p<0.001


Group p<0.001

Torque-Angle Curve of theTrunk Flexor Muscles

Position (degrees)

-50 -40 -30 -20 -10 0 10 20 30

To

rque

(N

m)

10

20

30

40

50

60

70

80

Postpartum

Control

FOLLOW UP


Position p<0.001


Group p=0.003

Fatigue Task

9/19/2016

32

Fatigability of the Trunk Flexor Muscles

Postpartum Control

Tim

e t

o T

ask

Failu

re (

s)

0

200

400

600

800

**


Postpartum Control

Tim

e to T

ask F

ailu

re (

s)

0

200

400

600

800

*INITIAL

FOLLOW UP

Impact of Method of DeliveryImpact of Method of DeliveryImpact of Method of DeliveryImpact of Method of Delivery


Vaginal Delivery

Cesarean Delivery

Tim

e t

o T

ask F

ailure

(s)

0

50

100

150

200

250

300

Fatigability of the Trunk Flexor Muscles6 Months Postpartum

Vaginal Delivery

Cesarean Delivery

Tim

e t

o T

ask F

ailu

re (

s)

0

100

200

300

400

P=0.004

P=0.523

Recovery of MVC Torque After Fatiguing Exercise

Task Failure r10 r20

MV

C (

% B

aselin

e)

60

70

80

90

100

110

120Control

Postpartum

INITIAL


Time p=0.023


Group p=0.139

FOLLOW UP


Time p<0.001


Group p=0.122



MV

C (

% B

aselin

e)

60

70

80

90

100

110

120Control

Postpartum

9/19/2016

33

Impact of Method of DeliveryImpact of Method of DeliveryImpact of Method of DeliveryImpact of Method of DeliveryTrunk Flexion MVC RecoveryVaginal vs Cesarean Delivery

Time


MV

C T

orq

ue (

% B

aselin

e M

VC

)

70

75

80

85

90

95

100Cesarean Delivery

Vaginal Delivery

Trunk Flexion MVC RecoveryVaginal vs Cesarean Delivery

6 Months Postpartum

Time


MV

C T

orq

ue (

% B

aselin

e M

VC

)

60

70

80

90

100

110

120

130

Vaginal Delivery

Cesarean Delivery

Time P=0.775

Time x Delivery Type

P=0.592

Delivery Type P=0.829

Time P=0.016

Time x Delivery Type

P=0.309

Delivery Type P=0.081


Task Failure r10 r20 Baseline

MV

C T

orq

ue (

Nm

)

10

20

30

40

50

60 Control

Postpartum

INITIAL


Time p<0.001

Time x Group p<0.001

Group p=0.001


Task Failure r10 r20 Baseline

MV

C T

orq

ue

(N

m)

10

20

30

40

50

60 Control

Postpartum

FOLLOW UP


Time p<0.001


Group p<0.001

Steadiness of contraction

9/19/2016

34

Force Fluctuations of Trunk Flexion Contractionsat Five Target Intensities

Coefficient of Variation of Torque

Target Intensity (% MVC)

0 10 20 30 40 50 60 70 80

CV

of

Torq

ue (

%)

0

5

10

15

20

25

30

35

40Control

Postpartum

INITIAL


Intensity p<0.001

Intensity x Group p=0.020

Group p=0.009

Force Fluctuations of Trunk Flexion Contractionsat Five Target Intensities

Coefficient of Variation of Torque

Target Intensity (% MVC)

0 10 20 30 40 50 60 70 80

CV

of

Torq

ue (

%)

0

10

20

30

40

50Control

Postpartum

FOLLOW UP


Intensity p<0.001

Intensity x Group p=0.219

Group p=0.039

Correlations

Association Between Maximal Strength and Fatigability of the Trunk Flexor Muscles


0 200 400 600 800 1000 1200 1400

MV

C S

trength

(N

m)

0

20

40

60

80

100

120r=0.602

p<0.001

N=44

Association Between Maximal Strength and Fatigability of the Trunk Flexor Muscles


0 200 400 600 800 1000 1200 1400 1600

MV

C S

trength

(N

m)

0

10

20

30

40

50

60

70

80

r=0.415

p=0.006

N=42

INITIAL

FOLLOW UP

9/19/2016

35

Association Between Trunk Flexor Fatigability andBody Fat Percentage (DXA)


0 200 400 600 800 1000 1200 1400

Body F

at (%

)

20

25

30

35

40

45

50

55

r=-0.342

p=0.023

N=44

Association Between Trunk Flexor Fatigability andBody Fat Percentage (DXA)


0 200 400 600 800 1000 1200 1400 1600

Bo

dy F

at

(%)

20

25

30

35

40

45

50

55

r=-0.402

p=0.008

N=42

INITIAL

FOLLOW UP

Association Between Trunk Flexor Fatigability andInter-Recti Distance at 4 cm Below the Umbilicus

(Measured with Ultrasound)


0 200 400 600 800 1000 1200 1400 1600

IRD

(cm

)

-1

0

1

2

3

4

5 r=-0.346

p=0.031

N=39

INITIAL

FOLLOW UP

Association Between Trunk Flexor Fatigability andInter-Recti Distance at 4 cm Below the Umbilicus



0 200 400 600 800 1000 1200 1400

IRD

(cm

)

-1

0

1

2

3

4

5r=-0.405

p=0.011

N=40

Association Between Trunk Flexor Maximal Strength and Thickness of Right Rectus Abdominis Muscle at 2.5 cm

Above the Umbilicus(Measured with Ultrasound)

MVC Strength (Nm)

0 20 40 60 80 100 120

Mu

scle

Th

ickn

ess (

cm

)

0.2

0.4

0.6

0.8

1.0

1.2

1.4

1.6r=0.311

p=0.040

N=44 Association Between Trunk Flexor Maximal Strength and

Thickness of Right Rectus Abdominis Muscle at 2.5 cm

Above the Umbilicus


MVC Strength (Nm)

0 10 20 30 40 50 60 70 80

Muscle

Thic

kne

ss (

cm

)

0.4

0.6

0.8

1.0

1.2

1.4r=0.388

p=0.012

N=41

9/19/2016

36

Association Between Trunk Flexor Maximal Strength andClinical Assessment of Abdominal Muscle Strength

(Manual Muscle Testing)

MVC Strength (Nm)

0 20 40 60 80 100 120

MM

T S

tre

ng

th G

rad

e

0

1

2

3

4

5

r=0.532

p<0.001

N=43

Association Between Trunk Flexor Maximal Strength andClinical Assessment of Abdominal Muscle Strength

(Manual Muscle Testing)

MVC Strength (Nm)

0 10 20 30 40 50 60 70 80

MM

T S

tre

ngth

Gra

de

0

1

2

3

4

5

r=0.621

p<0.001

N=38

Discussion

• Clinical implications of pregnancy & postpartum?

• Other clinical insights

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musculoskeletal health in women: impact of stress, aging ......aging “normal” aging •loss of...

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