CHANGES IN JUMP PERFORMANCE AND DYNAMIC BALANCE AT HIGH TERRESTRIAL ALTITUDE

The purpose of this study was to examine the effects of altitude on dynamic balance and jump performance of a controlled landing during a 12-day high altitude trek. Following a two-legged jump, time to stabilization (5% of body mass for 0.5 s), maximum power, and jump height were measured in 11 participants using a portable force platform at sea level (BL), 3619 m (C1), and 5140 m (C3). Jump performance significantly decreased at C1 and C3 compared to BL (P=0.001). There were no significant differences found in time to stabilization and maximum power with increasing altitude. The present findings indicate that jump performance is significantly decreased with increasing altitude. However, dynamic balance and jump power remain unaffected

THE ACUTE EFFECTS OF THE PREVENT INJURY ENHANCE PERFORMANCE PROGRAMME (PEP) ON ANTERIOR CRUCIATE LIGAMENT INJURY RISK FACTORS

The purpose of this study was to determine the immediate effects the prevent injury enhance performance programme (PEP) had on lower extremity biomechanics in relation to anterior cruciate ligament (ACL) risk factors compared to when it was not performed. 8 healthy males were required to perform a number of drop rebound jumps as a task that mimicked the sudden deceleration seen during ACL injuries. The PEP significantly (

ADAPTATIONS TO SPRINTING AND JUMPING AFTER TRAINING WITH A RESISTANCE HARNESS IN TRACK ATHLETES

This study examined the effect of a harness resisting leg movement on sprinting and jumping performance. Split times for 10, 20, 36.58 and 50 meters, kinematics of hip and knee angles during sprinting, forces of maximum countermovement jumps and dualenergy X-ray absorptiometry (DEXA) were measured prior and following five-weeks of training with the resistance device. Results showed significant improvement in 10 m sprint times and knee extension during sprinting following five-weeks training (p\u3c.05). No significant changes in jump or DEXA parameters were seen. Findings of the current study indicate that the SpeedMaker device may improve the acceleration phase of sprinting and stimulate a larger range of motion at the knee joint. Future studies with the device should include longer training periods, greater sample sizes and a measurement of resistance

ACUTE EFFECTS OF THE SPEEDMAKER RESISTIVE SPRINT DEVICE: ELECTROMYOGRAPHY AND KINEMATICS

The SpeedMaker resistive sprint device is claimed to elicit post-activation potentiation, improve knee height and upper leg drive to improve sprint performance. There was a total of 9 participants in the present study. The participants were tested on two days for changes in knee and hip angles, sprint times and changes in muscular activation. The present study found no presence of post-activation potentiation no evidence of changes improved knee height or upper leg drive from the SpeedMaker device. The purpose of the current study was to assess the claims that the SpeedMaker device improves sprint performance. The present study tested 10 female track and field and lacrosse athletes on the effects of this device. The findings of the present study is that the SpeedMaker device may decrease knee angle

A Comparison of Stride Length and Lower Extremity Kinematics during Barefoot and Shod Running in Well Trained Distance Runners

Stride length, hip, knee and ankle angles were compared during barefoot and shod running on a treadmill at two speeds. Nine well-trained (1500m time: 3min:59.80s ± 14.7 s) male (22 ±3 years; 73 ±9 kg; 1.79 ±0.4 m) middle distance (800 m – 5,000 m) runners performed 2 minutes of running at 3.05 m·s-1 and 4.72 m·s-1 on an treadmill. This approach allowed continuous measurement of lower extremity kinematic data and calculation of stride length. Statistical analysis using a 2X2 factorial ANOVA revealed speed to have a main effect on stride length and hip angle and footwear to have a main effect on hip angle. There was a significant speed*footwear interaction for knee and ankle angles. Compared to shod running at the lower speed (3.05 m·s-1), well trained runners have greater hip, knee and ankle angles when running barefoot. Runners undertake a high volume (~75%) of training at lower intensities and therefore knowledge of how barefoot running alters running kinematics at low and high speeds may be useful to the runner

Carriage rates, circulating serotypes and antibiotic resistance among Streptococcus pneumoniae in healthy infants in Yei, South Sudan

The carriage of Streptococcus pneumoniae, serotypes, antimicrobial susceptibility patterns and disease development are poorly understood in Yei. Availability of affordable antibiotics over the counter, lack of laboratory infrastructure and high rates of penicillin resistance have the potential to aggravate rates of childhood mortality associated with Streptococcus pneumoniae. There is an urgent need to strengthen microbiological and public health services

SYNCHRONIZATION AND TOWING EFFECT ON ADULT ONE-DOG CANICROSS PERFORMANCE

Canicross is competitive team sport in which a human athlete is towed via a canine athlete on an elastic gangline. Although human performance factors play a role in the success of the canicross team, the interaction between human and canine athletes may also play a crucial role on the performance of the team. The purpose of this study was to assess the synchronization patterns across different locations in competitive canicross events and investigate the influences of canine mass on a timed trial event. Video was taken at five locations along the trail of two different competitive canicross events. Synchronization was mapped and a total synchronization score was given to each of the 19 canicross teams. The results of the current study suggest that neither synchronization score nor human to canine mass ratios were correlated with performance

REACTIVE STRENGTH INDEX-MODIFIED IN DIFFERENT PLYOMETRIC TASKS

The Reactive Strength Index-Modified (RSl,d) is a reliable method of measuring the explosiveness of an athlete during a range of plyometric exercises. The purpose of the current study was to measure the between-limb differences in RSlmod across three different plyometric tasks. Eleven recreationally active participants performed countermovement jumps, stop jumps and single-leg jumps. The study found no significant differences in RSlmod between dominant and non-dominant limbs across all three tasks (p>0.05), but did find RSI,d to be higher in the stop jump than a countermovement jump and single leg stop jump for both dominant and non-dominant limbs. These findings show RSlmod may not be an indicator of limb asymmetry, but may be useful for the coach when looking to develop ex@losive performance in an athlete or performer

JOINT COORDINATION ADAPTATIONS TO AN IMPLEMENTED RAMP ANGLE IN RECREATIONAL ALPINE SKIERS

Most ski boot-binding complexes have a positive ramp angle. This angle is not regulated or reported in the alpine ski industry, but may influence skier balance and pressure control. Therefore joint coordination during a dynamic ski squat task with increasing boot ramp angle (0°, 1°, 2°) in alpine skiers (n=19) was investigated. Average joint coupling angles were significantly different between barefoot and ski conditions, as well as between the three ramp angles during the upward phase of a squat. The percentage of squat with uncoordinated knee-ankle joint movements tended to increase in ski conditions versus barefoot conditions, and coordinated hip-knee movement was reduced with alpine boot-binding-ski complexes. These differences in joint coordination and average coupling angles may impact skier balance and pressure control across the ski while skiing

REACTIVE STRENGTH INDEX-MODIFIED IN DIFFERENT PLYOMETRIC TASKS

The Reactive Strength Index-Modified (RSlmod) is a reliable method of measuring the explosiveness of an athlete during a range of plyometric exercises. The purpose of the current study was to measure the between-limb differences in RSlmod across three different plyometric tasks. Eleven recreationally active participants performed countermovement jumps, stop jumps and single-leg jumps. The study found no significant differences in RSlmod between dominant and non-dominant limbs across all three tasks (p\u3e0.05), but did find RSI,d to be higher in the stop jump than a countermovement jump and single leg stop jump for both dominant and non-dominant limbs. These findings show RSlmod may not be an indicator of limb asymmetry, but may be useful for the coach when looking to develop exPlosive performance in an athlete or performer