# EXERCISE-INDUCED ADAPTATIONS OF SKELETAL MUSCLE GRAFTS

> **NIH NIH R01** · UNIVERSITY OF MICHIGAN AT ANN ARBOR · 1988 · $45,995

## Abstract

Many characteristics of skeletal muscle grafts, including mass, functional
cross-sectional area, maximum tension development, and oxidative capacity,
remain below control muscle values.  These deficits potentially limit the
usefulness of the graft to the host organism in tasks requiring strength or
endurance.  In addition to transplantation, the degeneration of skeletal
muscle fibers occurs following a variety of diseases, trauma, and excessive
physical exercise (especially if lengthening contractions occur).
Regardless of the insult inducing degeneration, regeneration of muscle
fibers appears to follow a common pathway.  The objective is to determine
the effects of the intensity and duration of chronic exercise on the
structure and function of free and of vascularized skeletal muscle grafts.
In free grafts, the muscle will spontaneously revascularize and muscle
fibers will degenerate and new fibers will regenerate.  In vascularized
grafts, the fibers survive.  In both grafts, the fibers show a large
functional deficit compared to control muscle.  Hindlimb muscles will be
grafted orthotopically in rats.  Chronic physical activity patterns will be
changed by daily running on a motor driven treadmill an by ablation of
muscles synergistic to the graft.  It has been well documented in normal
muscle, and there are limited data on grafts, that chronic exercise of the
appropriate intensity and duration can increase variables which show a
deficit in grafts relative to control values.  The change of activity will
start at 28 days postgrafting and grafts will be studied through 112 days.
The capability of different chronic activity patterns to alter growth in
grafts that differ as to fiber type and anatomical site will be
investigated.  Outcomes will be evaluated by morphological (gross
dimensions, histochemistry), biochemical (protein concentrations, protein
turnover, metabolic marker) and physiological (contractile properties)
techniques.  Physical exercise is a complex stimulus to skeletal muscle in
terms of the type of contraction, the tension development during
contraction, and the frequency, intensity and duration of exercise
sessions.  Resolution of these complexities will provide the scientific
basis for establishing postgrafting procedures to improve the structure and
function of grafts in humans and in the rehabilitation of muscles in which
some fibers have regenerated due to disease, trauma or excessive exercise.

## Key facts

- **NIH application ID:** 3156782
- **Project number:** 5R01AR034298-03
- **Recipient organization:** UNIVERSITY OF MICHIGAN AT ANN ARBOR
- **SAM.gov UEI:** GNJ7BBP73WE9
- **Principal Investigator:** TIMOTHY P WHITE
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 1988
- **Award amount:** $45,995
- **Award type:** 5
- **Project period:** 1986-02-01 → 1990-01-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/3156782

## Citation

> US National Institutes of Health, RePORTER application 3156782, EXERCISE-INDUCED ADAPTATIONS OF SKELETAL MUSCLE GRAFTS (5R01AR034298-03). Retrieved via MORVS 2026-10-24 from https://api.morvs.ai/grant/nih/3156782. Licensed CC0.

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