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Suzie Godfrey and Stacy Winter

This paper presents a reflective account of the sport psychology support work delivered across one season at a professional football academy by a neophyte practitioner. The development of the sport psychology program, referred to as Winning Mentality, was guided by Harwood and Anderson's (2015) 5C guidelines to psychological skills training.The Winning Mentality program outlined within this paper was delivered to the U9-U12 age groups and focused on the three key topics: (1) growth mind-set; (2) emotional control; and (3) confidence.The intervention comprised predominantly of classroom-based workshops delivered at the team level that focused on one topic per training cycle. Working with these young age groups uncovered a number of challenges that form the basis of this reflective account.Drawing upon child developmental literature was a necessity to ensure the effective matching of session content to the relevant age group. In addition, the heavily classroom-based nature of the program limited the youth footballers application of sport psychology techniques on the football pitch.Finally, opportunities to empower coaches with the knowledge and skills to apply psychological concepts within their training sessions should be welcomed.

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John H. Lawrence III and T. Richard Nichols

Muscle actions are often defined within a single anatomical reference plane. Yet animals must control posture and movement within a three-dimensional (3-D) environment, responding to a 3-D array of perturbing forces. Based on information gained regarding the 3-D muscle mechanics at the cat ankle joint complex (companion paper), we decided to study how alterations in the 3-D AJC orientation might affect ankle joint postural control. We used a 6 degree-of-freedom force-moment sensor to assess the affect of ankle joint orientation on the 3-D isometric joint torques evoked by electrical stimulation of muscles crossing the ankle joint complex (AJC) in the deeply anesthetized cat. An orthogonal axis system was established at the designated ankle rotation center, such that pitch (flexion-extension), yaw (abduction-adduction), and roll (inversion-eversion) axis torques were calculated. Experimental results suggest that both the magnitude and sign of extra-sagittal torques from the gastrocnemius muscles are joint angle dependent. Also, the hind limb levering system stabilizes the AJC against large yaw and roll rotations away from the control position.

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Simon Roberts, Grant Trewartha and Keith Stokes

Purpose:

To assess the validity of a digitizing time–motion-analysis method for field-based sports and compare this with a notational-analysis method using rugby-union match play.

Method:

Five calibrated video cameras were located around a rugby pitch, and 1 subject completed prescribed movements within each camera’s view. Running speeds were measured using photocell timing gates. Two experienced operators digitized video data (operator 1 on 2 occasions) to allow 2-dimensional reconstruction of the prescribed movements.

Results:

Accuracy for total distance calculated was within 2.1% of the measured distance. For intraoperator and interoperator reliability, calculated distances were within 0.5% and 0.9%, respectively. Calculated speed was within 8.0% of measured photocell speed with intraoperator and interoperator reliability of 3.4% and 6.0%, respectively. For the method comparison, two 20-minute periods of rugby match play were analyzed for 5 players using the digitizing method and a notational time–motion method. For the 20-minute periods, overall mean absolute differences between methods for percentage time spent and distances covered performing different activities were 3.5% and 198.1 ± 138.1 m, respectively. Total number of changes in activity per 20 minutes were 184 ± 24 versus 458 ± 48, and work-to-rest ratios, 10.0%:90.0% and 7.3%:92.7% for notational and digitizing methods, respectively.

Conclusion:

The digitizing method is accurate and reliable for gaining detailed information on work profiles of field-sport participants and provides applied researchers richer data output than the conventional notational method.

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Kevin Currell, Steve Conway and Asker E. Jeukendrup

The aim of the study was to investigate the reliability of a new test of soccer performance and evaluate the effect of carbohydrate (CHO) on soccer performance. Eleven university footballers were recruited and underwent 3 trials in a randomized order. Two of the trials involved ingesting a placebo beverage, and the other, a 7.5% maltodextrin solution. The protocol comprised a series of ten 6-min exercise blocks on an outdoor Astroturf pitch, separated by the performance of 2 of the 4 soccer-specific tests, making the protocol 90 min in duration. The intensity of the exercise was designed to be similar to the typical activity pattern during soccer match play. Participants performed skill tests of dribbling, agility, heading, and shooting throughout the protocol. The coefficients of variation for dribbling, agility, heading, and shooting were 2.2%, 1.2%, 7.0%, and 2.8%, respectively. The mean combined placebo scores were 42.4 ± 2.7 s, 43.1 ± 3.7 s, 210 ± 34 cm, and 212 ± 17 points for agility, dribbling, heading, and kicking, respectively. CHO ingestion led to a combined agility time of 41.5 ± 0.8 s, for dribbling 41.7 ± 3.5 s, 213 ± 11 cm for heading, and 220 ± 5 points for kicking accuracy. There was a significant improvement in performance for dribbling, agility, and shooting (p < .05) when CHO was ingested compared with placebo. In conclusion, the protocol is a reliable test of soccer performance, and ingesting CHO leads to an improvement in soccer performance.

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Charles Thigpen and Ellen Shanley

Patient Scenario:

The patient presented is a high school baseball pitcher who was unable to throw because of shoulder pain. He subsequently failed nonoperative management but was able to return to pitching after surgery and successful rehabilitation.

Clinical Outcomes Assessment:

The Disabilities of Arm, Shoulder and Hand (DASH) and the Pennsylvania Shoulder Score (PENN) were selected as clinical outcome assessment tools to quantify the patient’s perceived ability to perform common daily tasks and sport tasks and current symptoms such as pain and patient satisfaction.

Clinical Decision Making:

The DASH and PENN provide important information that can be used to target specific interventions, set appropriate patient goals, assess between-sessions changes in patient status, and quantify patients’ functional loss.

Clinical Bottom Line:

Best clinical practice involves the use of clinical outcome assessment tools to garner an objective measure of the impact of a patient’s disease process on functional expectations. This process should facilitate a patient-centered approach by clinicians while they select the optimal intervention strategies and establish prognostic timelines.

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Darcy M. Brown, Dan B. Dwyer, Samuel J. Robertson and Paul B. Gastin

The purpose of this study was to assess the validity of a global positioning system (GPS) tracking system to estimate energy expenditure (EE) during exercise and field-sport locomotor movements. Twenty-seven participants each completed a 90-min exercise session on an outdoor synthetic futsal pitch. During the exercise session, they wore a 5-Hz GPS unit interpolated to 15 Hz and a portable gas analyzer that acted as the criterion measure of EE. The exercise session was composed of alternating 5-minute exercise bouts of randomized walking, jogging, running, or a field-sport circuit (×3) followed by 10 min of recovery. One-way analysis of variance showed significant (P < .01) and very large underestimations between GPS metabolic power– derived EE and oxygen-consumption (VO2) -derived EE for all field-sport circuits (% difference ≈ –44%). No differences in EE were observed for the jog (7.8%) and run (4.8%), whereas very large overestimations were found for the walk (43.0%). The GPS metabolic power EE over the entire 90-min session was significantly lower (P < .01) than the VO2 EE, resulting in a moderate underestimation overall (–19%). The results of this study suggest that a GPS tracking system using the metabolic power model of EE does not accurately estimate EE in field-sport movements or over an exercise session consisting of mixed locomotor activities interspersed with recovery periods; however, is it able to provide a reasonably accurate estimation of EE during continuous jogging and running.

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Martin Buchheit and Ben Michael Simpson

With the ongoing development of microtechnology, player tracking has become one of the most important components of load monitoring in team sports. The 3 main objectives of player tracking are better understanding of practice (provide an objective, a posteriori evaluation of external load and locomotor demands of any given session or match), optimization of training-load patterns at the team level, and decision making on individual players’ training programs to improve performance and prevent injuries (eg, top-up training vs unloading sequences, return to play progression). This paper discusses the basics of a simple tracking approach and the need to integrate multiple systems. The limitations of some of the most used variables in the field (including metabolic-power measures) are debated, and innovative and potentially new powerful variables are presented. The foundations of a successful player-monitoring system are probably laid on the pitch first, in the way practitioners collect their own tracking data, given the limitations of each variable, and how they report and use all this information, rather than in the technology and the variables per se. Overall, the decision to use any tracking technology or new variable should always be considered with a cost/benefit approach (ie, cost, ease of use, portability, manpower/ability to affect the training program).

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Mont Hubbard, Robin L. Hibbard, Maurice R. Yeadon and Andrzej Komor

This paper presents a planar, four-segment, dynamic model for the flight mechanics of a ski jumper. The model consists of skis, legs, torso and head, and arms. Inputs include net joint torques that are used to vary the relative body configurations of the jumper during flight. The model also relies on aerodynamic data from previous wind tunnel tests that incorporate the effects of varying body configuration and orientation on lift, drag, and pitching moment. A symbolic manipulation program, “Macsyma,” is used to derive the equations of motion automatically. Experimental body segment orientation data during the flight phase are presented for three ski jumpers which show how jumpers of varying ability differ in flight and demonstrate the need for a more complex analytical model than that previously presented in the literature. Simulations are presented that qualitatively match the measured trajectory for a good jumper. The model can be used as a basis for the study of optimal jumper behavior in flight which maximizes jump distance.

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Yin-Chou Lin, Angela Thompson, Jung-Tang Kung, Liang-Wei Chieh, Shih-Wei Chou and Jung-Charng Lin

Context:

Elbow injuries are widely reported among baseball players. The elbow is susceptible to injury when elbow-flexor and -extensor forces are imbalanced during pitching or throwing. Assessment of muscle-strength ratios may prove useful for diagnosing elbow injury.

Objective:

The purpose of this study was to assess the relationship between the elbow-flexor and -extensor functional isokinetic ratios and elbow injury in baseball players.

Design:

Retrospective study.

Setting:

Biomechanics laboratory.

Participants:

College baseball players with (n = 9) and without (n = 12) self-reported elbow pain or loss of strength were recruited.

Intervention and Main Outcome Measures:

Trials were conducted using a dynamometer to assess dominant-arm flexor and extensor concentric and eccentric strength at angular velocities of 60° and 240°/s. Functional isokinetic ratios were calculated and compared between groups.

Results:

Regression analysis revealed that a ratio of biceps concentric to triceps concentric strength greater than 0.76 (the median value) significantly predicted elbow injury (P = .01, odds ratio of injury = 24). No other ratios or variables (including position played) were predictive of injury status.

Conclusions:

These findings suggest that the ratio of biceps concentric to triceps concentric functional strength strongly predicts elbow-injury status in baseball players. Assessment of this ratio may prove useful in a practical setting for training purposes and both injury diagnosis and rehabilitation.

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Matt Greig and Philip Nagy

Context:

Epidemiological studies highlight a prevalence of lumbar vertebrae injuries in cricket fast bowlers, with governing bodies implementing rules to reduce exposure. Analysis typically requires complex and laboratory-based biomechanical analyses, lacking ecological validity. Developments in GPS microtechnologies facilitate on-field measures of mechanical intensity, facilitating screening toward prevention and rehabilitation.

Objective:

To examine the efficacy of using GPS-mounted triaxial accelerometers to quantify accumulated body load and to investigate the effect of GPS-unit placement in relation to epidemiological observations.

Design:

Repeated measures, field-based.

Setting:

Regulation cricket pitch.

Participants:

10 male injury-free participants recruited from a cricket academy (18.1 ± 0.6 y).

Intervention:

Each participant was fitted with 2 GPS units placed at the cervicothoracic and lumbar spines to measure triaxial acceleration (100 Hz). Participants were instructed to deliver a 7-over spell of fast bowling, as dictated by governing-body guidelines.

Main Outcome Measures:

Triaxial total accumulated body and the relative uniaxial contributions were calculated for each over.

Results:

There was no significant main effect for overs bowled, in either total load or the triaxial contributions to total load. This finding suggests no cumulative fatigue effect across the 10-over spell. However, there was a significant main effect for GPS-unit location, with the lumbar unit exposed to significantly greater load than the cervicothoracic unit in each of the triaxial planes.

Conclusions:

There was no evidence to suggest that accumulated load significantly increased as a result of spell duration. In this respect the governing-body guidelines for this age group can be considered safe, or potentially even conservative. However, the observation of higher body load at the lumbar spine than at the cervicothoracic spine supports epidemiological observations of injury incidence. GPS microtechnologies might therefore be considered in screening and monitoring of players toward injury prevention and/or during rehabilitation.