BIOMECHANICAL RISK FACTORS ASSOCIATED WITH NON-CONTACT ANTERIOR CRUCIATE LIGAMENT INJURIES DURING LANDING PERFORMANCE

Anterior cruciate ligament (ACL) injuries have received much attention in the biomechanics literature. The kinematics and kinetics of landing appear to be important risk factors for non contact ACL injuries especially for females. This paper reviews many of the some of the biomechanical factors that appear to be important to ACL injury risk and how recent modeling approaches have been utilized. Modeling studies depict a rather complex interaction of kinematic, kinetic and anatomical factors that result in ACL loading early in landing. More complex, subject and gender specific models may be important to gain further insight and thus influence injury prevention efforts

MOMENT AND POWER OF SHOULDER AND ELBOW IN SHOT-PUTTING

The purpose of this study was to quantify the moments and power of the elbow and shoulder joints. Three-dimensional methods and inverse dynamics were used to analyze the throwing arm of shot putter performing standing throws. The proximal to distal sequence was found on moments and power of the elbow and shoulder. The mechanical outputs from elbow and shoulder muscles were mainly energy generation

BIOMECHNICAL STRATEGY DURING PLYOMETRIC BARRIER JUMP- INFLUENCE OF DROP-JUMP HEIGHTS ON JOINT STIFFNESS

The purpose of this study was to explore the joint stiffness of lower-extremity during plyometric barrier jump. Fourteen power-oriented track and field men of collegiate and national level volunteered to participate in the study. All performed 3 maximal effort drop jumps where they landed and immediately jumped over a 60 cm barrier after dropping from 30, 60 and 90 cm. The results showed both knee and ankle joint stiffness became progressively and significantly lower with the increment of drop heights. Modulating knee and ankle joint stiffness, mainly by the joint angles during touchdown, is the biomechanical strategy to accommodate for changes in different drop heights. Our findings suggest the increment of drop heights during plyometric barrier jump diminished the benefit from stretch-shortening cycle

THE EFFECT OF DRIBBLING ON KNEE LOADING WHEN FEMALE BASKETBALL PLAYERS PERFORM SIDE STEP CUTTING MANEUVERS

Knee injuries in females seem related to movements during sports specific, high risk activities such as cutting. Loading on knee when the players make side step cutting maneuvers has been considered to be a factor related to Anterior Cruciate Ligament (ACL) injuries. Our purpose was to examine differences in female players performing a side step cutting with and without dribbling. Using 10 elite female basketball players, three dimensional kinematic and kinetic data were assessed. Based on our investigation, elite female basketball players performing a side step cut with dribbling exhibited greater knee valgus angles and moments. Sport-specific neuromuscular training programs for basketball players could consider may adding ball control tasks

Effects of Medially Wedged Foot Orthoses on Knee and Hip Joint Running Mechanics in Females With and Without Patellofemoral Pain Syndrome.

We examined the effects of medially wedged foot orthoses on knee and hip joint mechanics during running in females with and without patellofemoral pain syndrome (PFPS). We also tested if these effects depend on standing calcaneal eversion angle. Twenty female runners with and without PFPS participated. Knee and hip joint transverse and frontal plane peak angle, excursion, and peak internal knee and hip abduction moment were calculated while running with and without a 6° full-length medially wedged foot orthoses. Separate 3-factor mixed ANOVAs (group [PFPS, control] x condition [medial wedge, no medial wedge] x standing calcaneal angle [everted, neutral, inverted]) were used to test the effect of medially wedged orthoses on each dependent variable. Knee abduction moment increased 3% (P = .03) and hip adduction excursion decreased 0.6° (P < .01) using medially wedged foot orthoses. No significant group x condition or calcaneal angle x condition effects were observed. The addition of medially wedged foot orthoses to standardized running shoes had minimal effect on knee and hip joint mechanics during running thought to be associated with the etiology or exacerbation of PFPS symptoms. These effects did not appear to depend on injury status or standing calcaneal posture. ABSTRACT FROM AUTHO

A review of recent perspectives on biomechanical risk factors associated with anterior cruciate ligament injury

There is considerable evidence to support a number of biomechanical risk factors associated with non-contact anterior cruciate ligament (ACL) injury. This paper aimed to review these biomechanical risk factors and highlight future directions relating to them. Current perspectives investigating trunk position and relationships between strength, muscle activity and biomechanics during landing/cutting highlight the importance of increasing hamstring muscle force during dynamic movements through altering strength, muscle activity, muscle length and contraction velocity. In particular, increased trunk flexion during landing/cutting and greater hamstring strength are likely to increase hamstring muscle force during landing and cutting which have been associated with reduced ACL injury risk. Decision making has also been shown to influence landing biomechanics and should be considered when designing tasks to assess landing/cutting biomechanics. Coaches should therefore promote hamstring strength training and active trunk flexion during landing and cutting in an attempt to reduce ACL injury risk.Peer reviewe

The Influence of Backrest Inclination on Buttock Pressure

Objective To assess the effects of backrest inclination of a wheelchair on buttock pressures in spinal cord injured (SCI) patients and normal subjects. Method The participants were 22 healthy subjects and 22 SCI patients. Buttock pressures of the participants were measured by a Tekscan&reg; pressure sensing mat and software while they were sitting in a reclining wheelchair. Buttock pressures were recorded for 90&deg;, 100&deg;, 110&deg;, 120&deg; and 130&deg; seat-to-back angles at the ischial tuberosity (IT)and sacrococcygeal (SC) areas. Recordings were made at each angle over four seconds at a sampling rate of 10 Hz. Results The side-to-side buttock pressure differences in the IT area for the SCI patients was signifi cantly greater than for the normal subjects. There was no signifi cant diff erence between the SCI patients and the normal subjects in the buttock pressure change pattern of the IT area. Significant increases in pressure on the SC area were found as backrest inclination angle was changed to 90o, 100o and 110&deg; in the normal subjects, but no signifi cant diff erences were found in the SCI patients. Conclusion Most of the SCI patients have freeform posture in wheelchairs, and this leads to an uneven distribution of buttock pressure. In the SCI patients, the peak pressure in the IT area reduced as the backrest angle was increased, but peak pressure at the SC area remained relatively unchanged. To reduce buttock pressure and prevent pressure ulcers and enhance ulcer healing, it can be helpful for tetraplegic patients, to have wheelchair seat-to-back angles above 120&deg;

The impact of hoist sling materials on interface pressure whilst sitting in healthy volunteers and wheelchair users : a comparative study

Aim of the study To evaluate the effect of three sling fabrics on gluteal interface pressure whilst sitting in a population of wheelchair users and to compare these to data previously collected in a pilot study with a healthy population. Materials and methods A repeated measures experimental design was used with 32 adult wheelchair users (15 women, 17 men). Healthy population pilot study consisted of 61 participants (51 women, 10 men) recruited from staff and students at The University of Salford. Methods Gluteal pressures at six pressure zones were recorded using the X-sensor PX100 pressure sensor at 30 second intervals for 10 minutes. Data were collected in 4 conditions with participants seated in a standardised chair, followed by the chair with slings made of three different fabrics. Results The spacer fabric reduced the mean gluteal pressure more effectively than slipfit and polyester (p=0.014 and p=0.01 respectively, 95%CI) and reduced peak pressure at the left ischial tuberosity and coccyx when compared to the slipfit (p=0.003 and p=0.005) with the wheelchair users. When comparing data with the pilot study, the mean gluteal pressure and peak pressures at the ischial tuberosities and coccyx were significantly higher in the wheelchair user group (p&lt;0.005). Conclusion The fabric identified as the most effective in reducing mean and peak pressures in both groups was the spacer fabric, suggesting that a spacer fabric sling is more likely to reduce the risk of pressure ulcer development. This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors

An investigation of pressure ulcer risk, comfort and pain in medical imaging

In this study, we investigated the interface pressure of healthy volunteers on medical imaging (MI) table surfaces to determine the risks of developing pressure ulcers (PU). We also investigated volunteers’ perception of pain and comfort while lying on the MI table surfaces. Evidence from this study will enhance the understanding of factors contributing to PU formation and help improve service delivery to patients undergoing MI procedures