Abstract Archive

We analysed the rate of torque development (RTD) drop-off characteristics of forty anterior cruciate ligament (ACL) reconstructed (ACLR) subjects during maximal quadriceps voluntary isometric contractions (MVIC). We found that the RTD of ACLR limbs drops at a lower percentage of their maximum torque...

Ultrasonic measurements of rectus femoris echogenicity (ECHO) provide a measure reflecting infiltration of muscle by non-lean tissue (muscle quality). ECHO and subcutaneous fat thickness (SCFT) were related to mobility in older women with knee OA. Over and above obesity, muscle quality is associated...

This study tracked concussions and head impacts with helmet-mounted accelerometers over one high school football season and found that the weeks in which concussions occurred resulted in increased time spent on scrimmaging (a type of practice which simulates games) compared to other drills. These we...

This study investigated the relationship between muscle composition and patient-reported pain in individuals with and without symptomatic or radiographic hip osteoarthritis (OA). Fatty infiltration of the hip abductor muscles was quantified and related to HOOS pain scores. Increased fatty infiltrati...

Total Knee Arthroplasty (TKA) procedures are prevalent throughout the United States [1]. Patients often experience dissatisfaction and asymmetric gait post-TKA. Seven TKA patients conducted walking trials on three different terrains as well as completed a satisfaction survey. Initial findings identi...

Residual force depression (rFD) and residual force enhancement (rFE) are intrinsic contractile properties of skeletal muscle. To date, there have been no investigations of rFD and rFE in human fibres. Thus, the purpose of this study was to determine whether rFD and rFE occur at the single muscle fib...

Motor units control muscle function and coordination. However, most experimental and modelling motor unit recruitment studies have investigated isometric contractions, which limits its applicability to human movement. We introduce a musculoskeletal simulation framework that reverse engineers the rec...

We developed models to predict peak vertical ground reaction force (vGRF), vertical impulse, and contact time (tc) from running speed and a waist-mounted accelerometer. 25 collegiate cross country athletes ran at 3.8-5.4 m/s while we measured vGRF and sacral accelerations. We low-pass filtered accel...

The validity of sensorimotor balance control during walking was studied using foot placement and adjustment for foot placement during single stance. Nine stroke patients and 18 healthy controls performed a 2 minute walk test. Foot placement and adjustment for ‘incorrect’ foot placement (single s...

Falling forward on the outstretched hand is a common cause of injuries in older adults. Fall arrest mechanics in women have been investigated but sex-related aspects are currently unknown. To date, the biomechanics of 22 older adults (11 females) who completed forward descents on outstretched hands ...

To develop assistive devices that can account for muscle dynamics, we developed a machine learning algorithm that measures muscle fascicle lengths in real-time from live ultrasound imaging. Our algorithm’s predictions yielded up to 95% correlation and R2 = 0.89 with respect to hand-tracked images,...

Anterior cruciate ligament-deficient (ACL-D) individuals had a smaller total support moment (TSM) during stair descent compared to a control group. When examining joint components of the TSM, knee extensor and ankle plantarflexor moments were significantly reduced in the ACL-D group while the hip ex...

This study examined the role of cutaneous sensory feedback on the soles of the feet for a maximal motor output task. Participants performed maximum vertical squat jumps (MVSJ) under baseline, cooled, and recovered conditions. MVSJ height, jump preparation average force and impulse were lower in the ...

The purpose of this investigation was to examine a relationship between constraint of motion and motor output, in that use of an ipsilateral ankle foot orthosis-footwear combination maximizing constraint of ipsilateral ankle motion will minimize muscle activation. Our findings support a relationship...

Panoramic ultrasound has been used to measure muscle morphology – an important biomechanical parameter. However, the validity of this measure has yet to be shown in the hamstrings. Our preliminary results suggest good to excellent reliability of ultrasound for multiple hamstring muscle-tendon morp...

There are conflicting observations regarding residual force enhancement (RFE) in cardiac muscle. In this study, we intended to re-examine RFE in cardiac myofibrils. RFE was tested after active stretches from average sarcomere lengths of i) 1.8 to 2.0 µm (n = 8), and ii) 2.0 to 2.2 µm (n = 8). All ...

Walking independence is an important component of the elderly’s quality of life. Losses in muscle mass may impair mobility and reduce independence. Here we determined whether lower limb muscles’ thickness relates to and is able to explain the gait performance. Fifteen older individuals participa...

The aim of this study is to validate trunk, pelvis, hip, knee and ankle kinematics assessed by an inertial sensor system in healthy controls (HC) and persons with knee osteoarthritis (KOA) during a functional movement protocol. Therefore, kinematics were compared against an optoelectronic system. Th...

Previous reports suggest males have greater force steadiness compared to females [1]. This study showed females had greater variability in motor unit discharge rate and reduced force steadiness compared to males. The sex differences may be due to inherent biomechanical differences in tendon complian...

The highest prevalence of musculoskeletal disorders among women may be related to sex differences in associated biological factors such as postural biomechanics. The aim was to evaluate if there are sex differences in postures of upper limb, upper back, head and neck during a repetitive task perform...

Recording electromograpy (EMG) signals of deeply located muscles (e.g. iliopsoas) is challenging. The conventional surface and intramuscular EMG recording techniques present potential defects and risks, especially for the patients with pathological tissue close to the measurement site. In this study...

Side-to-side differences in knee biomechanics are considered risk factors for anterior cruciate ligament (ACL) injuries in sports. We found that progressive sport specific sensorimotor training (PSSMT) reduced flexion moment side-to-side differrence during a Drop Jump task. In contrast, machine base...

The rebound jump (RJ) is a mode of plyometric training that exploits a rapid cyclical muscle action known as the stretch-shortening cycle (SSC). Because landing from a rebound jump requires the athlete to modulate ground reaction forces of 3-14 times body weight, proper alignment and technique of th...

The purpose of this study was to determine the relationship between lean muscle volume of the thigh, calculated from MRI, and clinical mobility outcomes after accounting for thigh fatty tissue volume in women with knee osteoarthritis (OA). Secondarily, we aimed to quantify the relationship between l...

Neck pain (NP) is one of the most common and disabling musculoskeletal conditions in the world and is more prevalent in females. As a part of clinical examination for individuals with NP, ultrasound (US)-based imaging biomarkers of the cervical muscles have been increasingly utilized: cross sectiona...

General methods to predict rate of recovery of Whiplash associated disorder (WAD) patients rely on subjective functional assessments. The Neck Functional Holistic Analysis Score (NFHAS) stages patients into 5 groups according to the severity of ROM loss. In a cohort of 904 patients, the NFHAS showed...

Tackling is repetitively performed in rugby game play, critical to team performance, yet poor execution increase injury risk. Players are taught from a young age to engage in 1-on-1 lower or upper body tackles, yet limited research on whether coaching instruction can alter three-dimensional (3D) tac...

Patellar tendon and hamstring tendon grafts are two most common grafts in ACL reconstruction. Biomechanical differences of the knee function following ACL reconstruction with these grafts are still unclear. This study found some differences in sagittal plane kinetics during stair climbing.

The purpose of this study was to compare knee joint moments, kinematics and muscle activation between male and female team sport athletes during unanticipated sidestepping to further the understanding of sex-specific differences and their potential influence on anterior cruciate ligament (ACL) injur...

In this study we evaluated kinematic differences between thirty-one teen (13-18yr) males and females during unanticipated single-leg drop-jump landings. We found that females performed the drop-jumps with less trunk flexion and greater anterior pelvic tilt. These findings indicate a more erect landi...