Impact of Resistance Training-Protein Supplementation on Lean Muscle Mass in Childhood Cancer Survivors

This study is being conducted because low lean muscle mass is prevalent among childhood cancer survivors. Lean muscle is the non-fatty muscle tissue that makes up part of the body's lean body mass. Low lean muscle mass is associated with loss of overall body strength, declining mobility and eventually, loss of independence. Among childhood cancer survivors, low lean muscle mass may contribute to reduced physical functioning and a sense of fatigue with exertion, limiting ability to participate in adequate physical activity. Loss of strength and a sense of fatigue with repeated movement make it difficult to participate in daily activities.

Although there have not been exercise intervention studies among childhood cancer survivors specifically designed to evaluate the effects of resistance training on muscle mass, studies among individuals with chronic disease, including survivors of adult onset cancers, indicate that resistance exercise improves muscle mass, muscle strength, mobility, vitality and physical activity levels. Resistance training (weight lifting) is a form of physical activity that is designed to improve muscular fitness by exercising a muscle or a muscle group against external resistance.

The purpose of the study is to evaluate the effects of resistance training combined with either a protein supplement or a sports drink on changes in lean muscle mass in young adults who were treated for childhood cancer. The sports drink, for this study, is considered a placebo.

This double-blind placebo controlled study will randomize adult survivors of childhood cancer who are 18 to 44 years of age, greater than ten years post first cancer diagnosis, and with low lean muscle mass to two groups: Resistance Training + Supplement (RT+S) or Resistance Training + Placebo (RT+P). Randomization will be stratified by sex and age (18-29 and 30-44 years) in a block size of 4. Three weekly resistance training sessions will occur over a 24 week period. The participants, investigator, trainer and individuals involved in testing will be blind to group assignment.

Participants will receive information about physical activity and its health benefits. They will be randomly assigned to one of two groups to receive individually tailored resistance training three times per week for 24 weeks. One group will receive a protein supplement, while the other group will receive a sports drink (placebo).

To assess outcomes, participants will have the following research tests:

* Blood will be drawn to assess heart health.
* Questionnaires will be completed to assess physical activity and health as well as food intake.
* Blood pressure measurement.
* Electrocardiogram to assess heart health.
* Height, weight, waist and hip measurements.
* Lean muscle mass will be measured by dual x-ray absorptiometry (DEXA scan).
* Muscle strength will be measured by handgrip, knee extension, and ankle dorsiflexion.
* Walking speed to determine usual walking speed.
* Six-minute walk test to determine endurance.
* Physical activity will be monitored by having the participant complete a survey and wear a small recording device (accelerometer) for seven days.

Study Objectives:

* To evaluate the effects of 24-week supervised RT+S compared to RT+P on changes in lean muscle mass, muscle strength, walking speed, self-reported exhaustion and physical activity levels among childhood cancer survivors.
* To evaluate the effects of 24-week supervised RT+S compared to RT+P on changes in blood pressure, high density lipoprotein, triglycerides, abdominal obesity, fasting glucose, fasting insulin, and C-reactive protein among childhood cancer survivors.

Eligibility Criteria:
Inclusion Criteria:

* Participants must be enrolled on the SJLIFE protocol at St. Jude Children's Research Hospital.
* 18.0-44.99 years of age
* \>10 years post first cancer diagnosis.
* English speaking.
* Live within a 45-minute drive of a greater Memphis area ATC Fitness Center
* Low lean mass defined as either:

  * Age- and sex-specific relative lean muscle mass standard deviation score ≤ -1.0.

OR

* Body fat content greater than or equal to 25% in males or greater than or equal to 35% in females.

Exclusion Criteria:

* Currently pregnant (assessed by serum pregnancy test).
* Contraindications to resistance training or protein supplementation (e.g. renal) verified by a physician.