Hand Entry Research Articles

On the Learning, Transmission, and Embodiment of Swimming’s Haptic Grammar

This article develops the concept of ‘haptic grammar’ to encourage greater scholarly focus on the sensory aspects of bodily motion used to generate movement, knowledge of one’s body in an environment, and thus being-in-the-world. It ethnographically examines how swimmers learn specific motions – ‘the catch’, sculling, hand entry – to illustrate broader questions of how we learn to move our bodies. Focusing on these specific motions emphasises the importance of shared sensory knowledge and perception for learning enskilled bodily movement. More than simply knowing what to move when and how, learning how to sense how one moves one’s body parts is a crucial social process that swimmers become more skilful at via interlocutions among themselves and with their coaches regarding specific motions of specific body parts. This article illustrates how such socialised knowledge requires a shared haptic grammar to become more skilful at moving through the water and thus become ‘swimmers’.

Prediction of Shoulder Pain in Youth Competitive Swimmers: The Development and Internal Validation of a Prognostic Prediction Model

Background: Knowledge of predictors for shoulder pain in swimmers can assist professionals working with the athlete in developing optimal prevention strategies. However, study methodology and limited available data have constrained a comprehensive understanding of which factors cause shoulder pain. Purpose: To investigate risk factors and develop and internally validate a multivariable prognostic model for the prediction of shoulder pain in swimmers. Study Design: Cohort study; Level of evidence, 2. Methods: A total of 201 pain-free club- to international-level competitive swimmers were followed for 2 consecutive seasons. The cohort consisted of 96 male (mean ± SD age, 13.9 ± 2.2 years) and 105 female (13.9 ± 2.2 years) swimmers. Demographic, sport-specific, and musculoskeletal characteristics were assessed every 6 months. Swim-training exposure was observed prospectively. Shoulder pain interfering with training was the primary outcome. Multiple imputation was used to cope with missing data. The final model was estimated using multivariable logistic regression. We applied bootstrapping to internally validate the model and correct for overoptimism. Results: A total of 42 new cases of shoulder pain were recorded during the study. Average duration of follow-up was 1.1 years. Predictors included in the final model were acute:chronic workload ratio (odds ratio [OR], 4.31; 95% CI, 1.00-18.54), competitive level (OR, 0.19; 95% CI, 0.06-0.63), shoulder flexion range of motion, posterior shoulder muscle endurance (OR, 0.96; 95% CI, 0.92-0.99), and hand entry position error (OR, 0.37; 95% CI, 0.16-0.91). After internal validation, this model maintained good calibration and discriminative power (area under the receiver operating characteristic curve, 0.71; 95% CI, 0.60-0.94). Conclusion: Our model consists of parameters that are readily measurable in a swimming setting, allowing the identification of swimmers at risk for shoulder pain. Multivariable logistic regression showed the strongest predictors for shoulder pain were regional competitive swimming level, acute:chronic workload ratio, posterior shoulder muscle endurance, and hand entry error.

SHOULDER INJURIES IN TALENTED, COMPETITIVE SWIMMERS

BackgroundShoulder injuries are common in swimmers. However, prevalence and risk factors for shoulder injuries in talented, competitive swimmers are unknown.ObjectiveTo gain insight in the prevalence and risk factors for shoulder...

Prevalence of freestyle biomechanical errors in elite competitive swimmers.

Background:Poor freestyle stroke biomechanics is a suggested risk factor for shoulder pain and pathology, but this has not been proven in biomechanical or clinical studies. Furthermore, the prevalence of these theoretical errors has not been identified, which would help coaches, athletic trainers, and researchers determine the most appropriate errors to focus on and develop interventions.Hypothesis:The majority of swimmers will present with at least 1 freestyle stroke error.Study Design:Cross-sectional study.Level of Evidence:Level 4.Methods:Stroke biomechanics for 31 swimmers from a collegiate swimming team were captured using underwater/above-water cameras. Each video was evaluated for biomechanical errors: a dropped elbow during the pull-through phase, a dropped elbow during the recovery phase, an eyes-forward head-carrying angle, incorrect hand position during hand entry, incorrect hand entry angle, incorrect pull-through pattern, and inadequate body roll. Error prevalence was calculated, and relationships among the errors were evaluated using chi-square statistics.Results:A dropped elbow during the pull-through phase (61.3%) and a dropped elbow during the recovery phase (53.2%) had the highest prevalence. A dropped elbow during the recovery phase was significantly associated with a thumb-first hand entry angle (P = 0.027) and incorrect hand entry position (P = 0.009). An eyes-forward head-carrying angle was associated with an incorrect pull-through pattern (P = 0.047).Conclusion:Biomechanical errors potentially detrimental to the shoulder are prevalent among swimmers. Many of the errors were interrelated, suggesting that one error may lead to other errors.Clinical Relevance:These errors highlight the need for proper stroke instruction and evaluation to decrease the risk of shoulder injury in competitive swimmers.

Online Hand Written Character Recognition

Handwriting processing is a domain in great expansion. The interest devoted to this field is not explained only by the exciting challenges involved, but also the huge benefits that a system, designed in the context of a commercial application, could bring Two classes of recognition systems are usually distinguished: online systems for which handwriting data are captured during the writing process, which makes available the information on the ordering of the strokes, and offline systems for which recognition takes place on a static image captured once the writing process is over. The field of personal computing has begun to make a transition from the desktop to handheld devices, thereby requiring input paradigms that are more suited for single hand entry than a keyboard. Online handwriting recognition allows for such input modalities. On-line handwritten scripts are usually dealt with pen tip traces from pen-down to pen-up positions.

Kinematic differences between front crawl sprint and distance swimmers at a distance pace

The purpose of the study was to determine whether there are differences in kinematics between sprint and distance front crawl specialists when swimming at a distance pace using a six beat kick. Seven sprint and eight distance male specialists performed one maximum 400 m swim through a 6.75 m3 calibrated space recorded by six gen-locked cameras. The following variables were calculated: average swim velocity, stroke length, stroke frequency, upper limb and foot displacement, elbow angle, the shoulder and hip roll angle, duration of the stroke phases and time corresponding to particular events within the stroke cycle relative to hand entry. Differences between the groups were assessed by an independent t-test and effect size (d) calculations for each variable. The groups only differed significantly with respect to the average swim velocity, with the distance swimmers maintaining a greater velocity throughout the 400 m. However, effect sizes were moderate for elbow angle range during the pull phase (d = 0.78) and the total hip roll magnitude (d = 0.76). There was little evidence to suggest that sprint and distance swimmers using a six beat kick pattern differ in technique when swimming at a distance pace and therefore coaches should not encourage the development of different techniques between these groups.

Kinematic differences between front crawl sprint and distance swimmers at sprint pace

The purpose of this study was to use three-dimensional methods to determine whether there are distinct kinematic differences between sprint and distance front crawl swimmers when swimming at a sprint pace. Seven sprint and eight distance specialists performed four 25-m sprints through a 6.75-m3 calibrated space recorded by six gen-locked cameras. The variables of interest were: average swim velocity, stroke length, stroke frequency, upper limb and foot displacement, elbow angle, shoulder and hip roll angles, duration of stroke phases, and the time corresponding to particular events within the stroke cycle relative to hand entry. Differences between sprint and distance swimmers were assessed with an independent t-test for each variable, in addition to effect size calculations. Differences between sprint and distance front crawl swimmers were generally small and not significant when swimming at a sprint pace. Differences were limited to temporal aspects of the stroke cycle. These findings suggest that coaches should not train sprint and distance specialists differently in terms of technique development.

Automatic Storage and Analysis of Camera Trap Data

Automatic Storage and Analysis of Camera Trap Data

Stroking Characteristics during Time to Exhaustion Tests

Race analyses during swimming reveal how exercise duration affects both clean swimming speed (v), stroke rate (SR), and stroke length (SL). The aim of this study is to provide an explanation for the change of SL and SR during paced exercise swimming the front crawl through an analysis of intracycle changes in motor organization. Trained swimmers (N = 10) swam three times to exhaustion (TTE in seconds) at predetermined velocities corresponding to 95%, 100%, and 110% of the mean speed attained in a 400-m race (V 400). During TTE tests, SR, SL, durations of the glide + catch, pull, push, and recovery phases (s) were measured. Assessment of arm coordination was made through the calculation of the index of coordination (IdC). The time allotted to propulsion per distance unit was estimated (T prop). For all tested speeds, fatigue development induced a gradual increase of SR with concomitant decrease of SL. The duration of the nonpropulsive phases decreased, whereas the duration of the propulsive phases per stroke remained constant. The IdC increased reflecting a reduction of the lag time between two consecutive propulsive actions. Consequently, T prop increased. Fatigue development induced an increase of the SR to compensate for the reduced capacity to generate a propulsive impulse per stroke. The change in arm coordination allows a better chain of the propulsive actions and leads to a greater time allotted to propulsion per distance unit. Such motor adaptation ensures that the overall propulsive impulse remained constant whereas average propulsive force per arm stroke is reduced.

Using Electronic Scanning Forms for Data Entry

This article describes a technique for data entry of information obtained from interviews and questionnaires. Often, investigators have someone type information into an electronic computer database. This article describes the use of electronic scanning forms for data entry. Forms and equipment used for grading examinations may be used to record responses from questionnaires. This method of data entry is compatible with field research and can be quicker than hand entry of data.

Mass data massage: an automated data processing system used for NHEXAS, Arizona. National Human Exposure Assessment Survey.

Data entry and management are critical components of all large survey projects; data quality objectives must be met and data must be quickly and readily accessible. We developed a comprehensive system for data entry and management utilizing scannable forms with bubble fields and handwriting recognition. This 'Mass Data Massage' (MDM) system had three components: (1) form creation and database definition; (2) programming of data dictionaries for documentation and preliminary logic and range checks; and (3) data entry, management and documentation using the 'Mass Data Cleaning Program' (MDCP). Scannable forms were written in Teleform, where the data field definition, variable names and ranges were defined as the form was created. Completed forms were returned from the field, subjected to final field quality control (QC) checks, and transferred to the data management section. They were batched and coded as necessary. Once a batch of data was scanned and visually verified, the operator called up the menu for the MDCP. The MDCP had 31 program modules with 500-1200 lines of code each. The operator could select and run the appropriate dictionary on each data batch 'correcting' apparent errors in responses. This process was iterative until the data batch passed all dictionary checks. Proposed 'changes' were forwarded to the data coordinator (DC) for acceptance or rejection. After all errors had been resolved, each data batch was subjected to a 10% quality assurance (QA) check. The original data batch and associated file of applied changes were archived. Time expenditure using the scanning approach varied with the number of questions and the types of responses (handwritten or bubble fields). One-page forms took 42-60% of the time needed for hand entry; forms longer than 10 pages took 35-38% of the time. Use of faster machines will further speed the process. The main advantage of the system was the reduction of systematic errors. Scanning alone reduced errors found on 995 NHEXAS Baseline Questionnaires. Overall, the dictionary identified 0.55% errors on the scanned forms. Ten percent QC checks, performed on corrected batches ready for appendage to the master database, revealed an overall error rate of 0.02%. Similar checks on a laboratory form scanned from numeric handwriting detected 0.3% errors following dictionary application and 0.2% errors during the 10% QA check. This system was faster, more accurate, and more cost-effective than hand entry of data. A batch of data that took >1 week to process using the hand entry method was processed within 1 day using MDM. Human coding of specific answers and the final verification were the most time-consuming processes.

The Painful Shoulder During the Butterfly Stroke An Electromyographic and Cinematographic Analysis of Twelve Muscles

This paper compares the muscle firing patterns of 12 shoulder girdle muscles in competitive butterfly swimmers with painful and normal shoulders. Seven of the 12 muscles revealed statistically significant differences between the two populations. The posterior deltoid demonstrated more activity in the painful shoulders during hand entry while the upper trapezius and serratus anterior exhibited less activity. This alteration in muscle firing patterns allowed for the humerus to be positioned for a wider hand entry, which decreased the pain of impingement of the supraspinatus on the coracoacromial arch. Correspondingly, there was significantly less activity in the supraspinatus. The teres minor and serratus anterior revealed significantly less muscle action throughout pulling as they respectively failed to balance the humeral rotation and did not reverse their origins and insertions to pull the body over the arm. Also, the subscapularis and infraspinatus displayed increased activity in the painful shoulders as they depressed the humeral head to avoid impingement. There were no significant differences between the two groups in the rhomboids, pectoralis major, latissimus dorsi, or the anterior and middle deltoids. From this information, accurate preventative and rehabilitative exercise programs for the competitive butterfly swimmer can be developed.

The Normal Shoulder During the Butterfly Swim Stroke An Electromyographic and Cinematographic Analysis of Twelve Muscles

This study describes shoulder muscle activity during the butterfly stroke. Upon hand entry, the deltoids and rotator cuff muscles demonstrated activity as the humerus was abducted, extended, and externally rotated. The rhomboids and upper trapezius were also active, retracting and upwardly rotating the scapula, which positioned the glenoid for the humerus. During propulsion, the pectoralis major and latissimus dorsi generated power. The subscapularis and teres minor were active to control humeral rotation. The serratus anterior helped to pull the body over the arm by reversing its origin and insertion. The posterior deltoid completed humeral extension at the end of propulsion and began to lift the arm out of the water. Then, the middle and anterior deltoids fired with the supraspinatus and infraspinatus to abduct and externally rotate the arm. The scapular muscles were also active, retracting the proximal portion of the scapula while protracting and upwardly rotating the distal tip. The glenoid then provided a platform for the humerus. Overall, the serratus anterior and the subscapularis maintained a high level of activation throughout the stroke; thus, these muscles were highly susceptible to fatigue and vulnerable to injury.

The Normal Shoulder During the Backstroke

AbstractWe endeavored to clarify the role of the shoulder girdle during the backstroke. Twelve muscles of the shoulder girdle in competitive swimmers with normal shoulders were studied with fine-wire electromyography (EMG). The results demonstrated a similar pattern of activation at hand entry and h

The normal shoulder during freestyle swimming

The shoulder in swimming is subjected to multiple factors that can lead to a high injury rate. To prevent injury, one must understand the biomechanics of swimming. This paper describes the electromyographic and cinematographic findings of 12 shoulder muscles in competitive swimmers without shoulder pain. The results show the three heads of the deltoid and the supraspinatus functioning in synchrony to place the arm at hand entry and exit, the rhomboids and upper trapezius to position the scapula for the arm, the pectoralis major and latissimus dorsi to propel the body, the subscapularis and serratus anterior as muscles with constant muscle activity, the teres minor functioning with the pectoralis major, and the infraspinatus active only to externally rotate the arm at midrecovery. This information is important to design optimal preventative and rehabilitative exercise programs.

An Electrogoniometric Study of the Wrist and Elbow in the Crawl Arm Stroke

Abstract This study was undertaken to investigate the flexion and extension patterns of the wrist and elbow joints of varsity and untrained swimmers during the sprint crawl stroke. Eighteen subjects, representing the fastest swimmers from the Yale University Varsity Swimming Team, the Springfield College Varsity Swimming Team, and from swimming classes for men at Springfield College, were tested in 1966. Each subject sprinted the crawl stroke, from a dead start, four times over a distance of 20 yards. The wrist and elbow actions were recorded by means of waterproofed electrogoniometers attached to both wrists and both elbows, which continuously measured the angles and recorded on the oscillograph. Waterproofed transducers placed on each palm recorded on the oscillograph the instant of hand entry into the water and the exit from the water. It was found that, in spite of some differences between the groups, the overall patterns of movement were similar. The range within each group was such that for each var...