# BIOMECHANICS OF HIP AND KNEE

> **NIH NIH R01** · UNIVERSITY OF IOWA · 1987 · $154,961

## Abstract

The ability to determine muscle and joint forces in vivo is important for a
variety of reasons.  The two reasonable ways to do this at the present time
are to make direct measurements with implanted transducers and to calculate
the forces from mathematical models.  Each of the two techniques has
different advantages and disadvantages.  Thus, the two would be
complementary when combined.  The mathematical approach is noninvasive and
allows force determination in many situations and subjects, while the
direct measurements allow validation of the mathematical calculations, but
cannot be used in many situations.

We propose to develop an animal model in which we can make simultaneous
direct measurements and mathematical calculations of muscle and joint
forces.  Dogs will have multiple liquid metal strain gauges (LMSGs)
attached to hind limb tendons and foil gauges to the femoral neck.  The
dogs will be trained to walk in the gait laboratory and all measurements
necessary to calculate muscle and joint forces (displacement histories and
foot-floor reactions) will be made while recording output from the strain
gauges.  Simultaneous EMG recordings will also be made.  The animals will
then be sacrificed for post-calibration of the strain gauges so that we may
directly determine muscle and hip joint forces, to determine the inertial
properties of the body segments, and to create a muscle model.  The muscle
and joint forces will then be calculated and compared to the EMG recordings
and the measured muscle and joint forces.

We will also refine our mathematical models by:  (1) determining the
contributions of passive elements to the hip moments and determining their
effect on muscle and joint force predictions, and (2) developing a scheme
that guarantees continuous muscle function by accounting for the
contraction history.  The first of these two refinements will be
accomplished by experimentally measuring the passive moments at the hip in
human subjects and then incorporating those moments into the gait analyses
of the same subjects.  The second refinement will be accomplished by using
Hill's model to establish upper and lower bounds on the muscle force
predictions at each subsequent discrete time during the gait cycle for
which a muscle force is predicted.

## Key facts

- **NIH application ID:** 3154813
- **Project number:** 5R01AR014486-16
- **Recipient organization:** UNIVERSITY OF IOWA
- **SAM.gov UEI:** Z1H9VJS8NG16
- **Principal Investigator:** RICHARD A. BRAND
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 1987
- **Award amount:** $154,961
- **Award type:** 5
- **Project period:** 1973-05-01 → 1988-12-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/3154813

## Citation

> US National Institutes of Health, RePORTER application 3154813, BIOMECHANICS OF HIP AND KNEE (5R01AR014486-16). Retrieved via MORVS 2026-10-25 from https://api.morvs.ai/grant/nih/3154813. Licensed CC0.

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