Postpartum Exercise Intervention

Carroll University50 enrolled

Overview

The postpartum period is associated with decreases in physical activity levels, muscular strength, muscular endurance, and pelvic floor muscle function, but little scientific evidence exists on how best to initiate and progress exercise in the postpartum period. This proposal aims to improve habitual physical activity levels, neuromuscular health (i.e., strength, fatigability, symptom burden) and overall wellbeing (i.e., decreased fear of movement, improved sleep quality, improved perception of quality of life) through participation in a weekly exercise program. This study will help to inform postpartum exercise recommendations and is novel as it allows participants to incorporate their children into the exercise routine, thus removing a primary barrier to physical activity/exercise.

Physical activity (PA)/exercise is crucial for maternal health and wellbeing but several barriers to PA/exercise participation exist in the postpartum period. Musculoskeletal impairments-such as weakness, increased fatigability, pelvic floor dysfunction (e.g., incontinence, pelvic organ prolapse, etc.), and pain-are common in the postpartum period. While these impairments provide strong rationale for participation in PA/exercise, they can also act as barriers to participation. Several psychosocial barriers also exist, including fear of movement and lack of childcare. Despite the importance of PA/exercise for health and wellness, and the documented musculoskeletal impairments that are associated with the postpartum period, assessment of neuromuscular function and education on resuming exercise is lacking in the standard postpartum care model in the United States. In addition, conflicting information can be found on social media and among clinical experts on when and how to best resume PA/exercise after childbirth. This proposal will evaluate the influence of an eight-week exercise intervention on neuromuscular function (i.e., lower extremity strength \& endurance, pelvic floor muscle strength \& endurance, self-reported pelvic floor dysfunction symptoms), habitual physical activity levels, and overall wellbeing (i.e., levels of kinesiophobia, sleep quality, self-reported quality of life) in postpartum females. In an effort to decrease barriers to exercise, childcare will be offered, and participants will have the opportunity to incorporate their child(ren) into exercise sessions if they so desire. This proposal will utilize a randomized control trial (RCT) design and objective measures of strength (i.e., load cells) along with standard clinical assessments of pelvic floor muscle function (i.e., internal vaginal assessment of strength and endurance, self-reported symptoms using validated questionnaires).

Interventions

Progressive exerciseOTHER

A progressive, 8-week exercise intervention has been developed and will be administered in a group setting.

Active Straight Leg Raise TestDIAGNOSTIC_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.

Active Straight Leg Raise Fatigue TaskOTHER

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.

Lower Extremity Strength TestingOTHER

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.

Ultrasound imaging of abdominal wallDIAGNOSTIC_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.

Pelvic Floor Muscle Strength TestingOTHER

An internal vaginal pelvic floor muscle assessment will be performed at baseline and study completion by a licensed physical therapist with advanced training in pelvic floor muscle examination and treatment. Pelvic floor muscle function will be assessed using the PERFECT scale, which assesses both muscular strength ("P" for "power") and endurance ("E"). Strength is assessed by cueing the participant to perform a maximal voluntary pelvic floor muscle contraction while the examiner has their index finger inserted into the vagina. The modified Oxford scale is used to grade strength on a scale of zero (0) to five (5).

Pelvic Floor Muscle Endurance TestingOTHER

Pelvic floor muscle endurance is also assessed via the internal vaginal PFM examination. After strength testing is performed, participants are instructed to perform a maximal PFM contraction and hold for as long as possible (maximum of 10 seconds). The examiner counts the length of the contraction, and timing is stopped either when (1) strength of the contraction declines or (2) the maximum of 10 seconds is reached. The time in seconds is recorded.

Eligibility

Sex: FEMALEMin age: 18 Years

Medical Language ↔ Plain English

Inclusion Criteria: * 18 years of age or older * gave birth in the 24 months prior to study enrollment Exclusion Criteria: * less than 6 weeks postpartum or not medically appropriate to engage in exercise regardless of time since childbirth (will be screened using the Get Active Questionnaire for Postpartum) * prescription anti-inflammatory/pain medications that are taken daily; * significant orthopedic conditions that would contraindicate performance of the fatigue task and participation in the exercise intervention (such as fractures, severe scoliosis, etc) * moderate to severe cardiovascular \&/or pulmonary disease that contraindicates participation in exercise * neuromuscular health conditions (such as diabetes, neuropathy, multiple sclerosis, stroke, seizures, etc); * smoking/vaping or use of other tobacco or nicotine products (chewing tobacco, nicotine patches, nicotine gum, etc.) * use of any illegal drugs

Outcomes

Primary Outcomes

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

Physical activity habits around the time of testing will be assessed with a tri-axial accelerometer for 7 days outside of the laboratory, in part by measuring the TAC per day. TAC is the total number of filtered, full-wave rectified, integrated accelerations (all directions). These will then be averaged/day based on the total number of valid wear days for each participant.

Time frame: 7 days pre-intervention, 7 days post-intervention

Physical Activity Measured by Average Steps per day over 7 days

Physical activity habits around the time of testing will be assessed with a tri-axial accelerometer for 7 days outside of the laboratory, in part by measuring mean steps per day. This will be quantified as reported by the Ametris (formerly ActiGraph) accelerometer and CentrePoint analysis software. The Algorithm used by Ametris is not publicly available, but Ametris/ActiGraph accelerometers are frequently used in research quantifying physical activity.

Time frame: 7 days pre-intervention, 7 days post-intervention

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

Physical activity habits around the time of testing will be assessed with a tri-axial accelerometer for 7 days outside of the laboratory, in part by measuring mean duration per day of MVPA. Intensity of physical activity assessed using tri-axial counts (per the accelerometer software) are as follows: Light physical activity is between 200 and 2690 counts/min, moderate intensity between 2690-6166 counts/min, and vigorous intensity is ≥ 6167 counts/min. MVPA is ≥2690.

Time frame: 7 days pre-intervention, 7 days post-intervention

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

Physical activity habits around the time of testing will be assessed with a tri-axial accelerometer for 7 days outside of the laboratory, in part by measuring mean duration per day of MVPA. Intensity of physical activity assessed using vertical counts (per the accelerometer software) are as follows: Light physical activity is between 100 and 759 counts/min, moderate intensity is 760-5999 counts/min, and vigorous intensity is ≥ 6000 counts/min (MVPA is \> 760 counts/min).

Time frame: 7 days pre-intervention, 7 days post-intervention

Average Minutes per Day of Activity in at least 5-minute bouts

Physical activity habits around the time of testing will be assessed with a tri-axial accelerometer for 7 days outside of the laboratory, in part by measuring mean duration per day of all activity. Average minutes per day of activity within each of the following categories: light = 25.8 mg - 100.5 mg; moderate = 100.6 mg - 428.7 mg; vigorous = \> 428.8 mg (mg is the vector magnitude of acceleration calculated in gravities using Euclidean Norm minus 1 metric)

Time frame: 7 days pre-intervention, 7 days post-intervention

Average Minutes per Day of Activity in at least 10-minute bouts

Physical activity habits around the time of testing will be assessed with a tri-axial accelerometer for 7 days outside of the laboratory, in part by measuring mean duration per day of all activity. Average minutes per day of activity within each of the following categories: light = 25.8 mg - 100.5 mg; moderate = 100.6 mg - 428.7 mg; vigorous = \> 428.8 mg. (mg is the vector magnitude of acceleration calculated in gravities using Euclidean Norm minus 1 metric)

Time frame: 7 days pre-intervention, 7 days post-intervention

Physical activity levels via self-reported questionnaires

Participants will complete the International Physical Activity Questionnaire (IPAQ) short-form. The IPAQ short-form quantifies physical activity (PA) over the previous week in 2 categories: low, moderate, or high activity; or metabolic equivalents (MET) minutes per week. High PA is categorized as (1)vigorous PA on at least 3 days/week with a combined minimum of at least 1500 MET minutes/week or (2) 7 days of cumulative PA of any intensity that sums to a minimum total of at least 3000 MET minutes/week. Moderate PA is categorized as (1) 3+ days of at least 30 minutes of vigorous PA, (2) 5+ days of moderate PA or walking at least 30 minutes/day, or (3) 5+ days of any level of PA that sums to a minimum of 600 MET minutes/week. Low physical activity is categorized as activity that does not meet the criteria for medium or high activity.

Time frame: Once-a-week for the 8-week intervention period

Lower extremity strength

A straight leg raise maximal voluntary contraction (MVC) of each lower extremity will be performed in supine 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; the highest peak force will be considered the MVC. Only 1 MVC trial per leg will be performed following the fatigue task.