Physical Function Measures and Familiarization (1.5 hr)

Location: Center for Human Health and Performance

Intitute for Applied Life Sciences

UMass Amherst

The goal of this visit is familiarize participants with the study protocols and to assess mobility function.

Participants park for free at our building. We greet participants at the doors and walk them to each visit.

At Visit 1, participants will be asked to read and complete the Informed Consent document if they did not already complete the informed consent during a video chat. 

We measure blood pressure, height, and weight. 

Participants are asked to complete three mobility tests: 

1. Advanced Short Physical Performance Battery (SPPB-A), which involves:

• Balance stands where participants are asked to stand with their feet in 4 different positions for up to 30 seconds.

• Walking a straight, 6-meter path at usual speed (you will repeat this 4 times).

• Chair rises where participants are asked to stand from a chair ten times.

2. A 400-meter walk at a usual speed

3. Foot tapping test for 10 seconds (repeated twice on each foot)

Participants are shown the treadmill and asked to walk on it to become familiar with that feeling in preparation for Visit 3.

Particpants are familiarized with the strength testing procedures that they'll perform in Visit 3.

If someone thinks that they might be uncomfortable during the MRI, we can show them the MRI magnet (located at hMRC) that we will use for Visit 2. 

Lastly, we give participants a physical activity monitor, which is a small box that records the amount and intensity of physical activity performed over the next 10 days. Participants are instructed on how and when to wear this monitor as well as how to keep a simple physical activity log book. 

 Magnetic Resonance (MR) Visit (2.5 hr)

Location: Human Magnetic Resonance Center (hMRC)

Institute for Applied Life Sciences

UMass Amherst

The goal of this visit is to obtain images of the participants' thigh muscles and measure the metabolism in their muscle while they perform muscle contractions in a magnet. 

Upon arriving at the Center, we review the Magnetic Resonance Safety Form, and ask participants to remove all jewelry and change into their own shorts or our paper scrub pants. You will then walk through a metal detector (similar to those in airports) and we will use a wand metal detector to check that you are safe to enter the magnet room. 

Participants are escorted into the magnet room where they will lay on their back inside the scanner with their arms resting comfortably at their side. We lay a flexible mat on the thigh and use this mat to obtain images of the thigh muscles. This will take about 15 minutes. 

We will then remove that mat and position you with your leg on top of our leg exercise apparatus and a cuff similar to a blood pressure cuff around your thigh. Your lower leg will be strapped to the apparatus just above your ankle and at your knee using Velcro straps. Additional straps will also be secured over your hips to prevent unwanted movement during the muscle contractions that you will perform. A specially designed copper coil encased in a plastic box will be secured over your thigh muscles using Velcro straps. This coil will be used to measure changes in the chemistry of your muscle during the contractions. 

Headphones will be provided to limit the amount of noise from the scanner and to enable clear and constant communication between participants and the investigators. We will talk with participants and explain each set of measures as we go along. These measures are described next.

1. Maximal strength assessment: We ask participants to complete 2 sets of 3 rapid, maximal muscle contractions to determine their strength. One minute of rest is given between the 2 sets. For these, you will attempt to straighten your leg as quickly and forcefully as possible. The strap across your leg will prevent it from moving, and we will measure your strength during each contraction. 

2. Twelve maximal contractions: We ask participants to complete 24 seconds of maximal contractions, after which participants lie quietly inside the scanner, without moving, for 10 minutes. This procedure allows us to measure the thigh muscle’s aerobic capacity. 

3. Fatigue protocol: The fatigue protocl consists of 4-10 minutes of intermittent (one contraction every 2-10 seconds), low-to-moderate load contractions. We encourage participants to give their best effort throughout this protocol, which is designed to tire the leg. At the end of this 10 minutes, participants rest quietly in the magnet for 10 minutes while we continue to monitor the chemistry of the muscle. 

4. Cuff protocol: Participants will be lying quietly while the cuff around the thigh is inflated to 240 mmHg. The cuff will remain inflated for 8 minutes and then it will be released. This is done for measuring muscle metabolites and oxygen in the muscle.

Gait Analysis and Treadmill Walk Visit (3 - 3.5 hr)

Center for Human Health and Performance

Institute for Applied Life Sciences

UMass Amherst

The goal of this visit is to assess gait, mobility, and strength before and after a treadmill walk that is designed to mimic a walk that someone might take during their day.

Strength Testing

      Participants are asked to complete strength testing of their thigh muscle (that they practiced at the end of Visit 1)

Mobility Testing

Participants are asked to complete the mobility assessments that they performed during Visit 1 (balance stands, 6 meter walks, and chair rises).

Gait Analysis

For the gait analysis, participants are asked to change into a pair of shorts and provided with appropriately sized athletic walking shoes. Participants are outfitted with reflective markers on their foot, calf, thigh, hip, pelvis, shoulders, and arms. The position of the reflective markers will be recorded by high-speed cameras circling the data collection space. The cameras capture only the position of the reflective markers and the images do not contain any information that may be used to identify your person. Participants are asked to walk up and down the walkway about 10 - 12 times while measurements are made.

Treadmill walk

The prolonged walk protocol will begin on a level treadmill with the speed set at participants' preferred speed, determined at Visit 1. Challenge periods will occur at minutes 7, 17, and 27, where treadmill grade will be increased to 3% grade for 1 minute. This challenge is meant to mimic real world changes in incline that occur during a walk.

Optional Blood Draw and Biopsy Visit (1 - 1.5 hr)

Center for Human Health and Performance

Institute for Applied Life Sciences

University of Massachusetts Amherst

This visit is optional. The goal of this visit is to obtain a blood sample and a skeletal muscle biopsy from the thigh muscle to study how the thigh muscle cells work. 

Blood draw    

Participants will be asked to undergo a blood draw of 30 ml (~2 tablespoons). 

Biopsy

A trained physician will perform the needle biopsy procedure, which involves the removal and examination of a piece of muscle tissue. The muscle biopsy will be obtained under local anesthesia. A small incision (about 1 cm) is made into the skin and fascia. To take a biopsy, a needle is then inserted into the muscle. A small "plug" of tissue remains in the needle when it is removed from the muscle. This is about the size of 2-3 grains of rice. More than one needle insertion may be needed to obtain a large enough specimen for testing and examination.

The muscle that we will biopsy is on the outer thigh muscle, at a location of about mid-way between the knee and hip. Participants will feel some pressure or "tugging" sensations. Many people experience mild discomfort, but some people find the biopsy procedure painful. If there is pain, the physician will provide more anesthetic to the area to reduce the pain. After the anesthetic wears off, the area may be sore for about a week and may limit activity. We contact participants 24 and 72 hours after their biopsy to ensure that you are healing as expected.