Skier\u27s Edge: Biomechanical Analysis

ABSTRACT Skier’s Edge: Biomechanical Analysis Benjamin T. Johannes The Skier’s Edge trainer can be used by novice or expert skiers. Testing was performed to analyze if the use of the Skier’s Edge could reduce in shear forces of the valgus moment on the knee joint and anterior cruciate ligament (ACL) due to lesser fatigue of muscle and a higher hamstring to quadricep (H/Q) ratio activity. This leads to a reduction of improper form and an increase in balance. Experiments performed observed the change in muscle activity with the use of the Skier’s Edge over time when compared to other forms of workout (elliptical and or a traditional ski conditioning workout). Comparison of the three workout methods was completed by collecting kinematic, kinetic and electromyographic (EMG) data. Each participant, 9 male skiers (22±3 years old, 70.56±3.44 inches, 206±54 lbs.) and 6 female skiers (22±4 years old, 66.25±3.25 inches, 148±72 lbs.), were separated into even groups between the workout types. Data was collected initially and after a four-week period of exercise for each respective workout group. A relative valgus moment was found with the force and valgus angle data and an H/Q ratio was created using the vastus medialis and semitendinosus EMG data for the respective muscles. The findings of this study show that there were no significant differences between the workout types for either reduction of valgus moment or an increase in H/Q ratio which are indicators of reduced ACL injury. Trends in the data indicate that the elliptical workout may have a positive impact on H/Q when compared to the Skier’s Edge workout. Recommendation for future study includes having participants complete a more intense and longer workout period or to focus on the elliptical and Skier’s Edge workout to test for significant differences to aid in ACL injury reduction

Drop Vertical Jump Landing Mechanics Following Anterior Cruciate Ligament Reconstruction With and Without Lateral Extra-Articular Tenodesis

The use of combined anterior cruciate ligament (ACL) plus lateral extra-articular tenodesis (LET) reconstruction has shown promising results during clinical testing, however, no studies have examined its effectiveness during a dynamic functional task. We used the drop vertical jump (DVJ) to compare in vivo biomechanics of ACL reconstructed patients with and without LET. Our primary outcome was peak knee abduction moment during stance phase. Secondary kinetic and kinematic outcomes included peak initial contact and stance values for knee abduction angle, knee flexion moment and angle, knee internal rotation moment and angle, and vertical ground reaction force. We also assessed fear associated with physical activity between patients who were and were not able to perform the DVJ test. We found no significant differences between treatment groups at six months postoperative. This thesis presents the preliminary results of a continuing study and at this time no definitive conclusions can be made

Design and Evaluation of Pediatric Gait Rehabilitation Robots

Gait therapy methodologies were studied and analyzed for their potential for pediatric patients. Using data from heel, metatarsal, and toe trajectories, a nominal gait trajectory was determined using Fourier transforms for each foot point. These average trajectories were used as a basis of evaluating each gait therapy mechanism. An existing gait therapy device (called ICARE) previously designed by researchers, including engineers at the University of Nebraska-Lincoln, was redesigned to accommodate pediatric patients. Unlike many existing designs, the pediatric ICARE did not over- or under-constrain the patient’s leg, allowing for repeated, comfortable, easily-adjusted gait motions. This design was assessed under clinical testing and deemed to be acceptable. A gait rehabilitation device was designed to interface with both pediatric and adult patients and more closely replicate the gait-like metatarsal trajectory compared to an elliptical machine. To accomplish this task, the nominal gait path was adjusted to accommodate for rotation about the toe, which generated a new trajectory that was tangent to itself at the midpoint of the stride. Using knowledge of the bio-mechanics of the foot, the gait path was analyzed for its applicability to the general population. Several trajectory-replication methods were evaluated, and the crank-slider mechanism was chosen for its superior performance and ability to mimic the gait path adequately. Adjustments were made to the gait path to further optimize its realization through the crank-slider mechanism. Two prototypes were constructed according to the slider-crank mechanism to replicate the gait path identified. The first prototype, while more accurately tracing the gait path, showed difficulty in power transmission and excessive cam forces. This prototype was ultimately rejected. The second prototype was significantly more robust. However, it lacked several key aspects of the original design that were important to matching the design goals. Ultimately, the second prototype was recommended for further work in gait-replication research. Advisor: Carl A. Nelso

Design and Evaluation of Pediatric Gait Rehabilitation Robots

Gait therapy methodologies were studied and analyzed for their potential for pediatric patients. Using data from heel, metatarsal, and toe trajectories, a nominal gait trajectory was determined using Fourier transforms for each foot point. These average trajectories were used as a basis of evaluating each gait therapy mechanism. An existing gait therapy device (called ICARE) previously designed by researchers, including engineers at the University of Nebraska-Lincoln, was redesigned to accommodate pediatric patients. Unlike many existing designs, the pediatric ICARE did not over- or under-constrain the patient’s leg, allowing for repeated, comfortable, easily-adjusted gait motions. This design was assessed under clinical testing and deemed to be acceptable. A gait rehabilitation device was designed to interface with both pediatric and adult patients and more closely replicate the gait-like metatarsal trajectory compared to an elliptical machine. To accomplish this task, the nominal gait path was adjusted to accommodate for rotation about the toe, which generated a new trajectory that was tangent to itself at the midpoint of the stride. Using knowledge of the bio-mechanics of the foot, the gait path was analyzed for its applicability to the general population. Several trajectory-replication methods were evaluated, and the crank-slider mechanism was chosen for its superior performance and ability to mimic the gait path adequately. Adjustments were made to the gait path to further optimize its realization through the crank-slider mechanism. Two prototypes were constructed according to the slider-crank mechanism to replicate the gait path identified. The first prototype, while more accurately tracing the gait path, showed difficulty in power transmission and excessive cam forces. This prototype was ultimately rejected. The second prototype was significantly more robust. However, it lacked several key aspects of the original design that were important to matching the design goals. Ultimately, the second prototype was recommended for further work in gait-replication research. Advisor: Carl A. Nelso

A COMPARISON OF SELF-REPORTED AND FUNCTIONAL OUTCOMES BETWEEN USUAL AND A STAGED REHABILITATION PROGRAM POST ACL RECONSTRUCTION

ABSTRACT Six patients who underwent hamstring autograft ACL reconstruction were randomized into either Usual Care physiotherapy or the Staged Rehabilitation program. Patients in the Staged Rehabilitation program met with a physiotherapist at Fowler Kennedy Sports Medicine Clinic at two and six weeks post-surgery to go over a 12 week home-based program. At 12 weeks post-surgery, they continued their rehabilitation supervised by a physiotherapist focusing on sport-specific exercises. Patients in the Usual Care group met with a physiotherapist and scheduled supervised physiotherapy visits according to the therapist’s usual practice. This study did not find any statistically significant differences between groups for patient reported outcomes (ACL-QOL, LEFS, SF-12, IKDC Subjective, and P4), range of motion, hop testing and strength at six months post-surgery. These are the preliminary results of a larger continuing study; therefore definitive conclusions cannot be made

Wearable Sensors for Monitoring the Internal and External Workload of the Athlete

The convergence of semiconductor technology, physiology, and predictive health analytics from wearable devices has advanced its clinical and translational utility for sports. The detection and subsequent application of metrics pertinent to and indicative of the physical performance, physiological status, biochemical composition, and mental alertness of the athlete has been shown to reduce the risk of injuries and improve performance and has enabled the development of athlete-centered protocols and treatment plans by team physicians and trainers. Our discussions in this review include commercially available devices, as well as those described in scientific literature to provide an understanding of wearable sensors for sports medicine. The primary objective of this paper is to provide a comprehensive review of the applications of wearable technology for assessing the biomechanical and physiological parameters of the athlete. A secondary objective of this paper is to identify collaborative research opportunities among academic research groups, sports medicine health clinics, and sports team performance programs to further the utility of this technology to assist in the return-to-play for athletes across various sporting domains. A companion paper discusses the use of wearables to monitor the biochemical profile and mental acuity of the athlete

Enhancing Rehabilitation Following Anterior Cruciate Ligament Reconstruction

Thesis Title: Enhancing rehabilitation following anterior cruciate ligament reconstruction. Context: Physical training with a neuromuscular focus has been shown to reduce anterior cruciate ligament (ACL) injury. However, ACL injury remains prevalent and often leads to joint instability, which requires surgical reconstruction. Following reconstructive surgery, a minimum of 6 months supervised rehabilitation is recommended with associated with financial cost implications to the National Health Service (NHS), the patient and society. Traditionally rehabilitation is offered in a concurrent format, whereby strength and cardio-vascular endurance exercises are performed in the same session. However, accumulating evidence from healthy populations, suggests that the development of strength might be attenuated by cardio-vascular endurance conditioning performed in close temporal proximity. This thesis comprises an entirely novel investigation of potential attenuation of strength gains in rehabilitating clinical populations that is associated with temporal incompatibility of physiological conditioning stimuli. No study has previously investigated this phenomenon, whether it might compromise the efficacy of treatment or recovery, or its potential influence on objectively-measured and patients’ perception of functional, musculoskeletal and neuromuscular performance capabilities. Objectives: The purpose of this thesis was to assess the effects of reconstruction surgery and 24 weeks of non-concurrent strength and endurance rehabilitation (with 48 week post-operative follow-up) on (a) subjective (IKDC; KOOS; PP [Chapter 4]) and objective measures of function (HOP [Chapter 5]) (primary outcome measures for this thesis), and (b) objective measures of musculoskeletal (ATFD) and neuromuscular performance (PF, EMD, RFD, SMP [Chapter 5]) (secondary outcome measures), in patients with anterior cruciate ligament deficiency. The secondary aim was to evaluate the relationships amongst a subjective outcome of function (IKDC), an objective outcome of function (HOP), and the secondary objective outcomes of musculoskeletal (ATFD) and neuromuscular (PF, RFD, EMD, SMP) performance at pre-surgery and at 24 weeks post-surgery (Chapter 6). Setting: Orthopaedic Hospital NHS Foundation Trust. Design: Prospective random-allocation to group trial involving iso-volume rehabilitative intervention versus contemporary practice, using contralateral limb assessment and clinico-social approbation controls. The design compared the effects of experimental post-surgical rehabilitation comprising non-concurrent strength and endurance conditioning with two conditions of control reflecting contemporary clinical practice (matched versus minimal assessment interaction). Participants: Eighty two patients (69♂, 13♀, age: 35.4 ± 8.6 yr; time from injury to surgery 9.4 ± 6.9 months [mean ± SD]) electing to undergo unilateral ACL reconstructive surgery (semitendinosus and gracilis graft [n = 57]; central third, bone-patella tendon-bone graft [n = 25]); were allocated to groups (2:2:1 purposive sampling ratio, respectively). Nineteen patients were lost to follow-up. Intervention: A standardised traditional concurrent (CON) ACL rehabilitation programme acted as the control versus an experimental non-concurrent (NCON) ACL rehabilitation programme that involved separation of strength and cardio-vascular endurance conditioning. An additional control group (Limited testing CON) matched the CON group rehabilitation applied within contemporary clinical practice. Outcome Measures: Chapter 4: The self-perceived primary outcome measures of function IKDC, KOOS and PP were assessed on five separate occasions (pre-surgery, and at 6, 12, 24 and 48 weeks post-surgery). However, assessment occasions were purposefully reduced to pre-operative and 48 weeks post-operative for the Limited testing CON group. Chapter 5: The primary objective outcome of function was HOP; the secondary outcomes were ATFD, PF, RFD, EMD and SMP associated with the knee extensors and flexors of the injured and non-injured legs. These objective outcomes were assessed on five separate occasions (pre-surgery, and at 6, 12, 24 and 48 weeks post-surgery). However, assessment occasions were purposefully reduced to pre-operative and at 48 weeks post-operative only for the Limited testing CON group. Chapter 6 Self-perceived (IKDC) subjective knee evaluation and the objective outcome of function (HOP), and selected objective outcomes of musculoskeletal and neuromuscular performance including ATFD, PF, RFD, EMD and SMP of the knee extensors and flexors of the injured and non-injured legs where applicable; measured at pre-surgery and at 24 weeks post-surgery were analysed for association, using Pearson product-moment correlation coefficients. A priori alpha levels were set at p<0.05. Results: Chapter 4: Factorial analyses of variance (ANOVAs) with repeated-measures investigating the primary aim showed significant group (NCON; CON) by test occasion (pre-surgery, 6, 12. 24 and 48 weeks post-surgery) interactions for self-perceived outcomes of function IKDC, KOOS and PP confirmed increased clinical effectiveness of NCON conditioning (F(2.0, 82.9)GG = 4.0 p<0.05, F(2.2, 134.7)GG = 5.5 p<0.001, F(1.9, 121.4)GG = 14.6 p<0.001, respectively) and the group mean peak relative difference in improvement for NCON was ~5.9% - 12.7% superior to CON. The greatest interaction effect was found to occur between pre-surgery and the 12 weeks post-operative test occasion for IKDC and KOOS, and between pre-surgery and the 24 week test occasion for PP. Patterns of improvements in self-perceived fitness over time were represented by a relative effect size range of 0.71 to 1.92. Improvement patterns were not significantly different between control groups offering matched or minimised assessor-patient interaction (CON vs. Limited testing CON; pre-surgery vs. 48 weeks post-surgery) indicating that clinical approbation by patients had not contributed to the outcome. Chapter 5: Factorial analyses of variance (ANOVAs) with repeated-measures showed significant group (NCON; CON) by leg (injured/non-injured) by test occasion (pre-surgery, 6, 12, 24 and 48 weeks post-surgery) interactions of the objective measure of function (HOP) together with the secondary outcomes of ATFD, PF, RFD, EMD and SMP. Similar responses were noted for the knee extensors and flexors of the injured and non-injured legs (F(2.1, 248) GG = 4.5 to 6.6; p<0.01) and confirmed increased clinical effectiveness of NCON conditioning (range ~4.7% - 15.3% [10.8%]) better than CON between 12 and 48 weeks. Patterns of improvements in physical fitness capabilities over time were represented by a relative effect size range of 1.92 to 2.89. Improvement patterns were not significantly different between control groups offering matched or minimised assessor-patient interaction (CON vs. Limited testing CON; pre-surgery versus 48 weeks post-surgery) indicating that clinical approbation by patients had not contributed to the outcome. Chapter 6: Two-tailed probabilities were used due to the exploratory nature of this study. A limited number of weak to moderate statistically significant correlations were confirmed (ranging from r = 0.262 – 0.404; p<0.05; n=48 [amalgamated NCON and CON groups] ) between IKDC and most notably, the neuromuscular performance outcome of EMD. Conclusion: Overall, the patterning and extent of changes amongst self-perceived, functional, musculoskeletal and neuromuscular performance scores offer support for the efficacy of using non-concurrent strength and endurance conditioning to enhance post-surgery rehabilitation. The limited robustness of relationships amongst the validated and frequently-used self-perceived outcome of function [IKDC], and objectively-measured outcomes of function and musculoskeletal and neuromuscular performance suggested that each might properly reflect an important but separate aspect of clinical response and should be deployed to detect change

Physiotherapy goal setting in anterior cruciate ligament rehabilitation : an exploration of training, practice and beliefs

Despite the growing interest into the role of physiotherapists providing psychological interventions within anterior cruciate ligament (ACL), literature surrounding goal setting practices within this field is minimal. The main purpose of this research was to explore physiotherapists’ approaches, training and beliefs into goal setting practices used within ACL rehabilitation. The thesis consisted of seven chapters, two of which were empirical studies. The empirical chapters aimed to gain further insight into physiotherapists understanding on the psychological aspects of patients following ACL surgery, theoretical knowledge of goal setting, experiences of implementing goals, training received on goal setting and future training needs. Study four involved a UK cross sectional online survey of one hundred and twenty four physiotherapists (N=124). The survey provided an insight of perceptions and goal setting approaches used within ACL rehabilitation. These findings were further explored in study five which involved a UK semi-structured interview study including twenty four physiotherapists (N=24), using an inductive approach. Study five provided a much deeper understanding in to physiotherapist’s goal setting practices, training and experiences within ACL rehabilitation and also revealed issues surrounding the initial consultation process. The research findings were conceptualised into a theoretical, innovative goal setting model. The goal of this model is to outline a multi-phase conceptual model of an appropriate ACL rehabilitation goal setting strategy for physiotherapists in an attempt to guide both practice, teaching and research