Muscle Function After Childbirth

NCT05073224 | Suspended DMC

• 3 other identifiers: 2019-0275A536130Protocol Version 6/9/2020
• Study Type: interventional
• Target: 78
• Locations: 1 country
• Sites: 1

Brief Summary

This study will evaluate lower extremity and trunk neuromuscular control in 78 nulligravid and postpartum women. Participants will attend two experimental sessions, approximately 1 week apart, to assess neuromuscular function. Physical activity levels will also be assessed.

Conditions

Postpartum; Muscle Fatigue; Force Steadiness; Nulligravid; Muscle Weakness

Outcome Measures

Primary Outcomes (8)

• Incidence of Posterior Pelvic Pain

  The Active Straight Leg Raise (ASLR) test is a well-established clinical test that assesses stability of the lumbar spine/pelvis, posterior pelvic pain severity, and ability to activate the abdominal muscles. It is performed in supine. Participants are instructed to raise one leg, with the knee straight, to a heel height of 20 cm. The leg is held at the top for 5 seconds, then slowly lowered to the ground. The participant is asked to report pain on a 0 to 10 scale (0=no pain; 10=worst possible pain). The test is then repeated on the opposite limb.

  up to 10 days

• Incidence of Perceived Difficulty with ASLR Task

  The Active Straight Leg Raise (ASLR) test is a well-established clinical test that assesses stability of the lumbar spine/pelvis, posterior pelvic pain severity, and ability to activate the abdominal muscles. It is performed in supine. Participants are instructed to raise one leg, with the knee straight, to a heel height of 20 cm. The leg is held at the top for 5 seconds, then slowly lowered to the ground. The participant is asked to report perceived difficulty to raise the leg on a 0 to 5 scale (0=not at all difficult; 5=unable to lift leg). The test is then repeated on the opposite limb.

  up to 10 days

• Incidence of Lumbopelvic Instability

  The Active Straight Leg Raise (ASLR) test is a well-established clinical test that assesses stability of the lumbar spine/pelvis, posterior pelvic pain severity, and ability to activate the abdominal muscles. It is performed in supine. Participants are instructed to raise one leg, with the knee straight, to a heel height of 20 cm. The leg is held at the top for 5 seconds, then slowly lowered to the ground. The participant is asked to report perceived difficulty to raise the leg on a 0 to 5 scale (0=not at all difficult; 5=unable to lift leg) and pain on a 0 to 10 scale (0=no pain; 10=worst possible pain). If difficulty or pain are rated at a 1 or higher, the test is repeated with the researcher providing external compression of the pelvis. If perceived difficulty or reported pain are lower with compression, the test is considered positive for lumbopelvic instability. The test is then repeated on the opposite limb.

  up to 10 days

• Mean Time to ASLR Fatigue Task Failure

  For the ASLR Fatigue Task, the participant is instructed to maintain the elevated leg off the ground for as long as possible. Task failure will be defined as a heel height greater than or equal to 10 centimeters off the ground.

  up to 10 days

• Maximum Lower Extremity Strength: Leg

  A straight leg raise maximal voluntary contraction (MVC) of each lower extremity will be performed in the supine position before and within 2 minutes of completing the ASLR fatigue task with a custom made load cell instrumented strength testing device. This device consists of a rigid platform on which the study participant will lie supine. At the foot of the device is a tower that houses 2 load cells and is connected to a lightly padded push plate. This push plate can be raised and lowered such that the participant can push up into the plate (contacts the anterior surface of the participant's shin) or push down onto the push plate (contacts the posterior aspect of the participant's heel). Before the ASLR fatigue task, a minimum of 3 MVC trials will be performed on each leg, with a minimum of 1 minute rest between trials, in order to ensure a true maximum has been obtained; the highest peak force will be considered the MVC. Only 1 MVC trial per leg will be performed following the

  up to 10 days

• Maximum Lower Extremity Strength: Hip Extension

  A hip extension MVC will also be performed in supine (pushing down into the ground) on a force plate (1000 Hz) prior to performance of the ASLR fatigue task. Only the leg that will remain in contact with the force plate during the ASLR fatigue task (grounded limb) will perform the extension MVC, in order to normalize downward pressure into the force plate by the grounded limb during performance of the ASLR fatigue task. This will allow us to quantify activity of the grounded limb during the fatiguing task. A minimum of 3 hip extension MVCs will be performed, with 1 minute rest between trials. An MVC may also be assessed at the end of the fatiguing exercise bout.

  up to 10 days

• Limb Steadiness Measured by Limb Acceleration

  An inertial measurement unit (Trigno, Delsys, Boston, MA) will be placed on the test limb to track movement of the limb during performance of the ASLR Fatigue Task. Fluctuations in limb acceleration will be measured and quantified as the standard deviation of acceleration. Limb steadiness will be collected online, stored, and analyzed offline with ConsensysPRO software. The investigators hypothesize that fluctuations in limb acceleration will be greater among postpartum women as compared to nulligravid women during the performance of the ASLR Fatigue Task.

  up to 10 days

• Abdominal Fascial Integrity Measured by Mean Inter-Recti Distance

  Real time ultrasound will be used to assess inter-recti distance above and below the umbilicus. Participants will be assessed with B Mode images in supine at rest, in supine while lifting their head, and in supine while performing a straight leg raise.

  up to 10 days

Secondary Outcomes (18)

• Assessment of fatigability of the lumbopelvic stabilizing muscles measured by the ASLR Fatigue Task: Mean Ratings of Perceived Exertion (RPE)

  up to 10 days

• Assessment of fatigability of the lumbopelvic stabilizing muscles measured by the ASLR Fatigue Task: Mean Pain Score

  up to 10 days

• Average Total Activity Counts (TAC) per day over 7 days

  up to 7 days

• Physical Activity Measured by Average Steps per day over 7 days

  up to 7 days

• Mean Duration per day of Moderate-Vigorous Physical Activity (MVPA) over 7 days: tri-axial counts

  up to 7 days

Other Outcomes (3)

• Root mean square (RMS) of global EMG

  up to 10 days

• Percent of Maximum Voluntary Isometric Contraction (MVIC)

  up to 10 days

• Mean discharge rate of single motor units

  up to 10 days

Study Arms (2)

Postpartum

EXPERIMENTAL

Participants who are six months postpartum will complete 2 experimental sessions, separated by 7-10 days. Participants will complete multiple questionnaires, maximal voluntary contractions of the lower extremity muscles, clinical tests of lumbopelvic neuromuscular control/posterior pelvic pain provocation, and fatiguing lower extremity/trunk muscle exercise. Ultrasound imaging will be performed to measure inter-recti distance. Wireless Electromyography (EMG) sensors will be used to record EMG and limb steadiness (via Inertial Measurement Units (IMU). Physical activity will be measured by questionnaire and accelerometer.

Diagnostic Test: Active Straight Leg Raise Test; Other: Active Straight Leg Raise Fatigue Task; Other: Lower Extremity Strength Testing; Diagnostic Test: Ultrasound imaging of abdominal wall

Nulligravid

ACTIVE COMPARATOR

Participants who have never been pregnant will complete 2 experimental sessions, separated by 7-10 days. Participants will complete multiple questionnaires, maximal voluntary contractions of the lower extremity muscles, clinical tests of lumbopelvic neuromuscular control/posterior pelvic pain provocation, and fatiguing lower extremity/trunk muscle exercise. Ultrasound imaging will be performed to measure inter-recti distance. Wireless EMG sensors will be used to record EMG and limb steadiness (via IMUs). Physical activity will be measured by questionnaire and accelerometer.

Diagnostic Test: Active Straight Leg Raise Test; Other: Active Straight Leg Raise Fatigue Task; Other: Lower Extremity Strength Testing; Diagnostic Test: Ultrasound imaging of abdominal wall

Interventions

Active Straight Leg Raise Test DIAGNOSTIC_TEST

The ASLR test is a well-established clinical test that assesses stability of the lumbar spine/pelvis, posterior pelvic pain severity, and ability to activate the abdominal muscles. It is performed in supine. Participants are instructed to raise one leg, with the knee straight, to a heel height of 20 cm. The leg is held at the top for 5 seconds, then slowly lowered to the ground. The participant is asked to report perceived difficulty to raise the leg on a 0 to 5 scale (0=not at all difficult; 5=unable to lift leg) and pain on a 0 to 10 scale (0=no pain; 10=worst possible pain). If difficulty or pain are rated at a 1 or higher, the test is repeated with the researcher providing external compression of the pelvis. If perceived difficulty or reported pain are lower with compression, the test is considered positive for lumbopelvic instability. The test is then repeated on the opposite limb.

Also known as: ASLR Test

Nulligravid; Postpartum

Active Straight Leg Raise Fatigue Task OTHER

The protocol is similar to the ASLR test, except that the participant is instructed to maintain the elevated leg off the ground for as long as possible. A biofeedback air cuff will be placed under the participant's lumbopelvic region to assess movement of the spine/pelvis. The cuff will be inflated to 40 mm Hg, and the participant instructed to keep the needle as close to 40 mm Hg as possible throughout the test; no information will be provided on how to affect cuff pressure, but visual feedback of cuff pressure will be provided throughout the task. Ratings of perceived exertion (RPE) and pain will be obtained from participants every 30-60 seconds. Task failure will be defined as a heel height ≤10 cm or a change in cuff pressure ≥20 mm Hg. Both limbs will be tested, but in different sessions. The order of limb testing (dominant vs non-dominant) will be randomized and counter-balanced. Limb dominance will be self-reported.

Also known as: ASLR Fatigue Task

Nulligravid; Postpartum

Lower Extremity Strength Testing OTHER

A straight leg raise maximal voluntary contraction (MVC) of each lower extremity an MVC of the hip extensors of the grounded limb will be performed in supine before and within 2 minutes of completing the ASLR fatigue task. The straight leg raise MVC will be performed with a custom-made load cell instrumented strength testing device, which consists of a rigid platform on which the participant will lie. At the foot of the device is a tower that houses 2 load cells connected to a lightly padded push plate. The hip extension MVC will be performed on a force plate. Before the ASLR fatigue task, a minimum of 3 MVC trials will be performed for each muscle group, with a minimum of 1 minute rest between trials; the highest peak force will be considered the MVC. Only 1 MVC trial per muscle group will be performed following the ASLR Fatigue Task.

Nulligravid; Postpartum

Ultrasound imaging of abdominal wall DIAGNOSTIC_TEST

Real time ultrasound will be used to assess inter-recti distance above and below the umbilicus. Participants will be assessed with B Mode images in supine at rest, in supine while lifting their head, and in supine while performing a straight leg raise. The Principle Investigator has training and experience in musculoskeletal ultrasound.

Nulligravid; Postpartum

Eligibility Criteria

• Age: 20 Years - 35 Years
• Sex: female
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64)

You may qualify if:

• Post-partum
• Primiparous (this is their first child)

You may not qualify if:

• multiple gestation
• prescription anti-inflammatory/pain medications that are taken daily
• significant orthopedic conditions that would contraindicate performance of the fatigue task (such as fractures, severe scoliosis, etc)
• cardiovascular \& pulmonary disease
• neuromuscular health conditions (such as diabetes, neuropathy, multiple sclerosis, stroke, seizures, etc)
• history of previous abdominal surgery (with the exception of Cesarean delivery)
• Nulligravid Women (Controls)
• Women from the surrounding community will also be recruited to serve as controls

Sponsors & Collaborators

• Carroll University: lead

Study Sites (1)

Carroll University

Waukesha, Wisconsin, 53186, United States

Location

MeSH Terms

Conditions

Muscle Weakness

Condition Hierarchy (Ancestors)

Muscular Diseases; Musculoskeletal Diseases; Neuromuscular Manifestations; Neurologic Manifestations; Nervous System Diseases; Pathologic Processes; Pathological Conditions, Signs and Symptoms; Signs and Symptoms

Study Officials

• Rita Deering, PT, DPT, PhD

  Carroll University

  PRINCIPAL INVESTIGATOR

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: NON RANDOMIZED
• Masking: NONE
• Purpose: BASIC SCIENCE
• Intervention Model: PARALLEL
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Associate Professor

Study Record Dates

• First Submitted: September 28, 2021
• First Posted: October 11, 2021
• Study Start: September 20, 2022
• Primary Completion (Estimated): December 1, 2026
• Study Completion (Estimated): July 1, 2027
• Last Updated: March 10, 2026

Record last verified: 2026-03

Data Sharing

• IPD Sharing: Will not share

Locations

US (1)