Spinal cord nocireceptive neurones

These electrophysiological investigations of spinal cord neu¬ rones responding to noxious and non-noxious cutaneous stimulation were conducted to evaluate (1) their ascending projection into the spinothalamic tract, (2) the involvement of endogenous opioids in mediating the tonic descending and segmental inhibition and (3) the role of the nucleus locus coeruleus (LC) in modulating spinal cord nociceptive transmissionA total of 252 neurones were antidromically activated from the ventrolateral quadrant but only 14 of these were found to project into the spinothalamic tract. The spinothalamic tract (STT) neurones responded to noxious and non-noxious, or to noxious stimulation alone. All the units were located in lamina VII and most of them displayed wide receptive fields. None of the 39 specific nociceptor-driven neurones from lamina I was found to project into the spinothalamic tract.Naloxone (0.3-2.0 mgm/kg) did not alter the response of multireceptive neurones to heat, to tonic descending inhibition or to the inhibition generated by stimulation of contralateral plantar nerve or dorsal columns.Stimulation in the nucleus locus coeruleus produced a predominantly inhibitory effect on nociceptive transmission in the spinal cord. The descending inhibition produced from LC was antagonised by the administration of a-noradrenergic receptor antagonists but was not changed by 3-receptor antagonists. Methysergide did not alter the inhibition from LC or NRM whereas the GABA antagonist, bicuculline, abolished the inhibition. Naloxone partially reduced the inhibition from LC. The ipsilateral ventral quadrant lesion (VLF and VF) abolished the actions produced from LC but a bilateral DLF lesion was required for abolishing the NRM actions. Electrolytic lesions made in the midline raphe complex did not block the actions produced from LC. The stimuli in LC and NKM that evoked inhibition of multireceptive neurones also produced DRPs.These data support the conclusion that the spinothalamic tract in the cat plays a role in the transmission of nociceptive and tactile messages to the brain. The endogenous opioids do not appear to be involved in mediating the types of inhibition examined (Section III). The descending actions produced from LC are not mediated through NRM and are most probably mediated through the direct coeruleospinal projection. Catecholaminergic, opioid and Gabaergic transmission is involved in mediating these actions which may involve both the pre- and postsynaptic mechanisms

EFFECTS OF SIX WEEKS OF TRAINING ON INTERSEGMENTAL COORDINATION IN THE ROWING STROKE OF NOVICE INTERCOLLEGIATE ROWERS

The purpose of the study was to examine changes in coordination during the rowing stroke after 1 and 6 weeks of practice. Initially 11 healthy, females who had elected to join a college rowing program volunteered to participate in both testing sessions: Only 3 participants were still on the novice team at wk 6, thus N=3. Participants were video taped on a land ergometer in 2D using the Peak Motion Measurement System. SPC was assessed between adjacent 2-segment combinations of the T-S (trunk-shoulder), K-T (knee-trunk), and S-E (shoulder-elbow) to quantify intersegmental coordination. Mean changes in T-S (78.7% v 74.6 %), K-T (66.5% v 102.9%) and S-E (88.2% v 71.3%) showed that the rowing stroke is primarily a simultaneous pattern. However. individual SPC (shared positive contribution) changes varied indicating that 6 wks is not a long enough for coordination to develop in novice rowers

Does core strength training influence kinetic efficiency, lower extremity stability, and 5000m performance in runners?

Context: Core strength training (CST) has been popular in the fitness industry for a decade. Although strong core muscles are believed to enhance athletic performance, only few scientific studies have been conducted to identify the effectiveness of CST on improving athletic performance. Objective: Identify the effects of a 6-wk CST on running kinetics, lower extremity stability, and running performance in recreational and competitive runners. Design and Setting: A test-retest, randomized control design was used to assess the effect of CST and no CST on ground reaction force (GRF), lower extremity stability scores, and running performance. Participants: Twenty-eight healthy adults (age, 36.9+9.4yrs, height, 168.4+9.6cm, mass, 70.1+15.3kg) were recruited and randomly divided into two groups. Main outcome Measures: GRF was determined by calculating peak impact vertical GRF (vGRF), peak active vGRF, duration of the breaking or horizontal GRF (hGRF), and duration of the propulsive hGRF as measured while running across a force plate. Lower extremity stability in three directions (anterior, posterior, lateral) was assessed using the Star Excursion Balance Test (SEBT). Running performance was determined by 5000 meter run measured on selected outdoor tracks. Six 2 (time) X 2 (condition) mixed-design ANOVA were used to determine if CST influences on each dependent variable, p \u3c .05. Results: No significant interactions were found for any kinetic variables and SEBT score, p\u3e.05. But 5000m run time showed significant interaction, p \u3c .05. SEBT scores improved in both groups, but more in the experimental group. Conclusion: CST did not significantly influence kinetic efficiency and lower extremity stability, but did influence running performance

VERTICAL JUMP PERFORMANCE DURING VIDEO SIMULATED BLOCKING AND MAXIMAL EFFORT JUMPING IN FEMALE COLLEGIATE VOLLEYBALL PLAYERS

This study’s purpose was to compare jump height, velocity and force production between video simulated blocking, [reactive timing (RT) jump], and maximal effort vertical jumping, [self-select timing (SST) jump]. 10 female collegiate volleyball players performed both jumps onto a force plate in a laboratory while being videotaped with one camera. Jump heights(cm), velocities(m/s), and forces(%BW) were calculated using Peak Motus. A RMMANOVA identified differences in the dependent variables across the two jumps. Jump height and peak velocity were significantly higher in the SST jump, 52.20+8.43 v 38.33+11.76 cm, and 5.69+0.71 v 5.4+0.61 m/s, respectively,

GAIT PATHOMECHANICS AS DIFFERENTIATORS OF PERFORMANCE IN COLLEGIATE DISTANCE RUNNERS: A TEAM CASE ANALYSIS

The purpose of the study was to determine if gait pathomechanics could differentiate between top and bottom performing runners. Two top-performers and two bottom-performers from both men’s and women’s college cross-country teams underwent motion analysis while running on a treadmill in the pre-participation medical examination. Bottom-performing males had greater peak hip adduction, hip internal rotation, contralateral pelvis drop, rearfoot eversion, and initial impact (vGRF) during stance than top-performing males. Bottom-performing females had greater hip internal rotation and vGRF than top-performing females. Coaches may use these results to promote proper running mechanics, especially in younger runners to not only reduce injury risk but to improve performance.

DIFFERENCES IN ANGULAR VELOCITY AMONG SELECTED KINEMATICS DURING A LEFT-HANDED PITCHER’S PICK-OFF MOVE

Previous research on the left-handed pitcher’s pick-off move has only focused on angular displacements. The purpose of this study was to analyze differences in angular velocity among selected kinematic variables between a pick-off move to first base and a normal delivery to home plate. Kinematic data were collected on pitchers (n=10) performing deliveries to first and home. Significant differences existed in nearly all of the kinematic variables. The timing of these differences can be used to aid baserunners in determining at which angles and at what times they should focus their attention

EFFECTS OF 6 WKS OF YOGA TRAINING ON SELECTED MEASURES OF STATIC AND DYNAMIC BALANCE

The purpose of this study was to measure the effects of 6 wks (2 xlwk) of Hatha yoga training on selected measures of static and dynamic balance. Initially, 30 adult, healthy males and females volunteered for this study. At 6 wks, nyoga = 6, nCOnlrol = 7. All participants underwent one static and two dynamic tests on a force plate prior to and 6 wks into the stUdy. SO of the COP in the x and in the y directions were averaged for each test and compared between groups and across time using mixed model ANOVAs. The only significant difference was the main effect for time on NP leg swing (dynamic balance) in the x direction. Mean differences were observed for the yoga group in both dynamic balance tests in the x direction. We suggest a training stimulus of 2 sessions/wk and/or 6 wks of yoga is not adequate to significantly influence static and dynamic balance

ARE FUNCTIONAL MOVEMENT PATTERNS PRECURSORS TO FUNCTIONAL PERFORMANCE IN UNIVERSITY WOMEN’S SOCCER PLAYERS?

Functional movement patterns (e.g., stepping, lunging) underlie higher-order skills (e.g., throwing, jumping). Thus, better jump performance may be associated with higher Functional Movement Screen (FMS) scores. We examined this relationship in 25 female university soccer players. Pearson Correlation was used to determine associations between FMS scores (out of 21) and CMJ height (cm), reactive strength (RSI-mod, m/s), and peak concentric, eccentric and landing forces (N/kg). FMS (14.68 ± 2.43) was moderately associated with jump height (23.78 ± 5.94 cm), r(23)=0.54, p≤0.05 and RSI-mod (0.22 ± 0.06 m/s), r(23)=0.44, p≤0.05. University women’s soccer players who had higher FMS scores also jumped higher and had greater reactive strength. Ensuring functional movement pattern proficiency may enhance CMJ performance

DELIVERIES TO HOME PLATE AND FIRST BASE MADE BY LEFT-HANDED BASEBALL PITCHERS

The purpose of this study was to analyze differences between the delivery to home plate and first base of left-handed baseball pitchers and, subsequently, quantify the pick-off move. Seven healthy participants were used in the study, and all were current or former collegiate pitchers. Deliveries to both targets were captured in three dimensions, and selected kinematics were used for comparison. Results showed that of the selected kinematics, only upper torso rotation (UTR) displayed both statistically significant differences as well as differences that could be detected in game situations. Other measurements showed differences in their means, but were not disparate enough to be considered reliable for use in game strategy. High-level left-handed pitchers maximize their natural advantage

CONTACT TIME, FLIGHT TIME AND GROUND REACTION FORCES DURING A CONTROLLED RUNNING TRIAL OF ELITE AMERICAN FOOTBALL PLAYERS

Running speed is influenced by vertical ground reaction force (vGRF) application, foot-ground contact time (Tc), flight time (TF), and time taken to reposition the limbs in swing. The purpose of this study was to investigate running speed modulators in two groups of elite American football players [Skill (i.e. wide receivers, defensive backs, n=8) and Big Skill (i.e. linebackers, tight ends, n=8)]. Subjects ran at 6.5 m/s for 5 sec on an instrumented treadmill. Peak vGRF, Tc and TF were examined for overall associations and compared between groups. Tc was strongly associated with vGRF, p\u3c.001. Big Skill had larger absolute vGRF, p=.012 than Skill. Skill players had larger TF, smaller TC, and smaller relative vGRF, although not significant. Elite American football players apply large forces over long foot-ground contact time during a controlled ru