Center Grants

2007 Pilot Grant Awards

2008 Pilot Grant applications due May 16

Principal Investigator:
Scott McLean, Ph.D.
Assistant Professor
Athletic Training Education Program
Division of Kinesiology
University of Michigan

Title of Project:
“Efficacy of Current ACL Injury Prevention Methods under Exposure to a Realistic Sports Environment”

Award Amount:
$39,979

Abstract:

Sports-related ACL injuries continue to present as a serious and largely unexplained clinical dilemma. Currently, knee joint kinematic factors considered “high risk” are elucidated and screened via state-of-the-art motion capture methods. This strictly lab-based approach, however, has limited applicability to the true random sports environment, and does not afford instantaneous athlete feedback that may otherwise promote successful neuromuscular adaptation. Herein we propose to develop and validate an alternative technology aimed at addressing these limitations explicitly. This technology, using light weight and extremely compact MEMS inertial sensors has the potential to significantly improve current ACL injury risk detection and prevention methods and to translate to other sports injury mechanisms. The current study aims to: 1) Develop a prototype MEMS system capable of quantifying knee joint kinematics during dynamic lower limb motions; Evaluate the efficacy of this measurement system during 2) Simulated (mechanical system) and 3) In vivo knee joint postures of increasing dynamic complexity. We will initially develop a prototype device based on our previously established designs for sports training aids. Above and below knee sensors will be fabricated and integrated within a novel body-worn measurement device wired to a light-weight (Palm Pilot) real-time data acquisition system. Temporarally based error functions will be obtained by comparing benchmark prototype and 3D motion capture kinematic outputs obtained for the pre-mentioned simulated and in vivo motion trials. Function norms will subsequently be defined, providing a scalar description of prototype efficacy for experimental case. If successful, this technology will enable extreme joint postures to be readily assessed within the true sports environment, providing the impetus for immediate and substantial further research. It will also facilitate the next important step towards the identification and subsequent prevention of realistic neuromechanical contributors to ACL injury risk. This will ultimately afford increased participation, quality of life and a reduced potential for long-term debilitation in a large number of relatively young individuals.

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Principal Investigator:
Riann Palmieri-Smith, Ph.D.
Assistant Professor
Athletic Training Education Program
Division of Kinesiology
University of Michigan

Title of Project:
“Neuromechanical Consequenses of Arthogenic Muscle Inhibition.”

Amount of Award:
$39,754

Abstract:

Approximately 200,000 individual suffer anterior cruciate ligament (ACL) ruptures annually in the U.S. A common clinical obstacle associated with ACL rupture and subsequent ACL reconstruction is an inability to achieve full voluntary activation of the quadriceps musculature. Quadriceps inhibition is thought to be the result of a neural inhibition preventing full voluntary muscle activation and is referred to as arthrogenic muscle inhibition (AMI). AMI hinders rehabilitation by preventing gains in strength, increasing the risk of re-injury, and potentially placing patients at risk for post-traumatic osteoarthritis. While much attention has been placed on identifying AMI after injury, little work has been conducted examining its consequences. The proposed research will determine: 1) the magnitude of quadriceps inhibition necessary to result in biomechanical and neuromuscular adaptations and 2) the feasibility of introducing neuromuscular electrical stimulation in rehabilitation post-ACL reconstruction to restore quadriceps activation and normal mechanics. We will capture the central activation ratio to assess quadriceps inhibition and lower extremity kinematics and kinetics during a forward hopping task to assess biomechanical adaptations. We hypothesize that 1) lower extremity mechanics and neuromuscular function will be dependent upon the magnitude of quadriceps inhibition and 2) neuromuscular electrical stimulation will increase quadriceps activation thereby improving lower extremity mechanics.

Relevance: ACL injury poses a high probability of lifetime compromise in physical functioning, as 70% ruptures ultimately result in osteoarthritis. Quadriceps inhibition is present following ACL injury and reconstruction and often persists for years following repair and its consequences remain elusive. Our work will allow for a better understanding of how muscle dysfunction impacts joint protective mechanisms. Introducing therapies focused on reducing AMI may promote sustained improvements in quadriceps activation thereby restoring lower extremity mechanics and potentially reducing the incidence of post-traumatic osteoarthritis. This knowledge will aid clinicians in designing appropriate rehabilitation protocols and return to play guidelines that will prevent future injury and joint degeneration.

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Principal Investigator:
Dr. Jolie Holschen
Assistant Professor of Emergency Medicine and
Orthopaedic Surgery
University of Michigan

Title of Project:
“Gender Differences in Neuropsychologic Parameters, Risk of Sustaining Concussion, and Recovery after Mild Traumatic Brain Injury.”

Amount of Award:
$40,000

Abstract:

The CDC estimates that over 1.4 million people sustain a traumatic brain injury (TBI) each year in the U.S. About 75% of TBI that occur each year are concussions or mild TBI (MTBI). Up to 15% of patients diagnosed with MTBI may have persistent disabling symptoms. Adolescents and young adults are at the highest risk of sustaining a MTBI, while the pediatric brain is thought to be even more vulnerable. MTBI costs approximately $17 billion each year (CDC 1999). MTBI is likely to become an even bigger problem as Americans are increasingly encouraged to engage in physical activity to improve their health.

One of the leading causes of MTBI includes sports activities. A recent study among high school athletes found that over 1 in 8 of 1.4 million injuries reported were concussions. In our emergency department at the University of Michigan, 25% of concussions were sustained via participation in sports between 2005–2006 years. The percentage related to sports participation approached 70% when studied in the pediatric population. Recent NCAA data indicates that per exposure, women are at a higher risk of sustaining a head injury than men. For example, in 2005-05, collegiate women soccer players sustained concussions at a rate of 2.30 vs. 1.24 in men (13.9% vs. 6.3% of total injuries).

The sex hormones have been studied in animal models and in patients with severe TBI. Progesterone administration has been shown to be neuroprotective, associated with decreased cerebral edema, reduced mortality, and improved functional outcomes. Interestingly, hormones have been implicated in the risk of other injuries, including sprains, anterior cruciate ligament tears, and fractures. Perhaps the risk of all of these injuries has a common specific causal factor, which this study postulates is the effect of hormones on brain processing and reaction time.

This study will enroll seventy 15–24 y.o. injured and thirty uninjured, male and female subjects presenting to the Adult or Pediatric Emergency Department and the NeuroSport Clinic at the University of Michigan. Survey, observational, and neuropsychological data will be evaluated. Urine and blood sampling will be performed and banked for future protein and DNA analysis.

The results of this study have major implications for female athletes, as well as physicians treating patients who have sustained a MTBI. If it can be shown that the increased risk of MTBI in women is due to neurocognitive differences, then strategies can be implemented to improve these parameters and decrease the risk of injury. In addition, if the risk of concussion is found to be influenced by the menstrual cycle, many elite athletes may choose to reduce this variable through use of oral contraceptive pills.

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Principal Investigator:
Dr. James K. Richardson
Physical Medicine and Rehabilitation
University of Michigan

Title of Project:
“Can a Clinical Measure of Reaction Time Predict a Sports-Specific Protective Response?”

Amount of Award:
$40,000

Abstract:

Reaction time (RT) is important to the evaluation of sport-related concussion (SRC), with prolongation of RT often persisting beyond the point of clinical recovery and clearance for return to play. However, RT is most commonly measured with a personal computer and dedicated software, making its measurement unavailable to most athletes, particularly younger athletes who may be at increased risk for sequelae related to SRC. To expand the availability of RT measurement, we developed a clinical measure of RT (RTclin) using a simple, inexpensive, portable tool (a vertical cylinder which is released and caught as quickly as possible) that was a valid and reliable measure of RT in pilot studies. We will study 26 health young subjects, using kinematic and myoelectric methods, and pursue 2 aims:

The first aim is to test the hypothesis that RTclin predicts a sport-related protective reaction time (SPRT; raising the hands to protect the face and head from a projectile) with, and without, the prior administration of lorazepam, which is known to prolong RT by a central neurologic mechanism. If the hypothesis is confirmed the validity of RTclin with respect to a functional task relevant to the prevention of injury, the avoidance of a direct blow to the head or face is supported.

The second aim is to test the hypothesis that pre-motor time, rather than the other two components of RT (electromechanical delay and movement time), is primarily responsible for the lorazepam-induced prolongation of RTclin and SPRT. Because pre-motor time includes central neurologic events, data confirming this hypothesis support the validity of RTclin in the evaluation of associated delay in phalangeal or upper extremity acceleration. A sideline tool that can evaluate rapid central processing time is novel, and will be of benefit in monitoring the effects of sport-related head trauma and guiding decisions regarding return to play.

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