Wrist kinematics during pitching. A preliminary report

Percutaneous Threaded Pin Fixation of Distal Radius Fracture in the Athlete

BACKGROUND

The purpose of this study was to examine the outcomes and return to play with early rehabilitation in athletes who sustained unstable extra-articular distal radius fractures treated with a purpose-designed threaded pin technique.

METHODS

This prospective study examined athletes with displaced and unstable distal radius fractures treated surgically with purpose-designed threaded pins. Patients were enrolled in an early rehabilitation protocol, with formal therapy initiated on postoperative days 1 to 3. Range of motion and strength measurements were documented throughout the postoperative period, noting the time until return to athletic competition. These results were compared with historical values using other forms of fixation.

RESULTS

Nineteen athletes, average age of 35 years, were treated with threaded pin technique with early rehabilitation; all had complete healing and maintained alignment based on radiographic evaluation. The average time span between surgery and release to competition was 8 weeks, with all but 1 patient returning to sport within 12 weeks of injury. Average postoperative flexion measured 58°, extension was 57°, pronation was 81°, and supination was 74°. JAMAR grip strength in position 3 measured 25.22 kg, which equated to 73% of the uninjured side's grip strength at the time of release to play.

CONCLUSIONS

Surgical fixation using a purpose-designed threaded pin is a useful alternative to volar plating for isolated radial styloid and extra-articular distal radius fractures in athletes. The purpose-designed threaded pin may afford athletes rapid recovery during the early postoperative period, preserving strength and dexterity and minimizing time lost before return to play.

A Biomechanical Analysis of the Association Between Forearm Mechanics and the Elbow Varus Moment in Collegiate Baseball Pitchers

BACKGROUND

The incidence of upper extremity injury in baseball pitchers has increased over the past decade. This has resulted in a large body of research mainly focused on the kinematic and kinetic patterns of the elbow and shoulder to elucidate the cause of these injuries, with little attention on studying the associations of forearm rotation and upper arm joint moments.

HYPOTHESIS

There will be significant differences in forearm kinematics and kinetics when comparing the fastball pitch with the curveball pitch. There will be a positive association between forearm kinetics, specifically supination and pronation moments, and the elbow varus moment.

STUDY DESIGN

Descriptive laboratory study.

METHODS

A total of 78 pitchers were recruited for this study, and they underwent a pitching analysis using motion analysis techniques. A random-intercept, mixed-effects regression model was used to determine differences in forearm kinematics and kinetics when pitching a fastball compared with a curveball, as well as to determine if associations existed between forearm supination and pronation moments and the elbow varus moment.

RESULTS

There were a number of significant differences in forearm position when pitching a fastball compared with a curveball, with the curveball producing a more supinated forearm position. Significant associations were found between increasing forearm supination moments and an increase in elbow varus moment for both the fastball and the curveball ( P = .002 and P < .001, respectively). For every 1-N·m increase in the supination moment, there was a 1-N·m and 1.1-N·m increase in the elbow varus moment for the fastball and curveball, respectively.

CONCLUSION

The results demonstrated that the forearm position was not associated with the elbow varus moment. However, the supination moment was associated with the elbow varus moment.

CLINICAL RELEVANCE

On the basis of these findings, pitching coaches and trainers can understand the implications of proper lower arm pitching mechanics in the later portion of the pitch cycle as a potential risk of injury and, therefore, can develop coaching strategies to reduce incorrect positioning, especially when players are pitching the curveball.

A kinematic comparison of the overhand throw and tennis serve in tennis players: how similar are they really?

Tennis coaches often use the fundamental throwing skill as a training tool to develop the service action. However, recent skill acquisition literature questions the efficacy of non-specific training drills for developing complex sporting movements. Thus, this study examined the mechanical analogy of the throw and the tennis serve at three different levels of development. A 500 Hz, 22-camera VICON MX motion capture system recorded 28 elite female tennis players (prepubescent (n = 10), pubescent (n = 10), adult (n = 8)) as they performed flat serves and overhand throws. Two-way ANOVAs with repeated measures and partial correlations (controlling for group) assessed the strength and nature of the mechanical associations between the tasks. Preparatory mechanics were similar between the two tasks, while during propulsion, peak trunk twist and elbow extension velocities were significantly higher in the throw, yet the peak shoulder internal rotation and wrist flexion angular velocities were significantly greater in the serve. Furthermore, all of these peak angular velocities occurred significantly earlier in the serve. Ultimately, although the throw may help to prime transverse trunk kinematics in the serve, mechanics in the two skills appear less similar than many coaches seem to believe. Practitioners should, therefore, be aware that the throw appears less useful for priming the specific arm kinematics and temporal phasing that typifies the tennis serve.

The management of ulnocarpal abutment and degenerative triangular fibrocartilage complex tears in the competitive athlete

Ulnar-sided wrist pain is a frequent cause for loss of practice time and competitive play for athletes. Ulnocarpal abutment, a common source of ulnar-sided pain, typically burdens athletes who participate in gymnastics, racket sports, and baseball. Although many athletes respond to nonoperative management, surgical intervention should be considered when symptoms persist. Surgical options include arthroscopic debridement, arthroscopic wafer, open wafer, or ulnar-shortening osteotomy. Treatment should be tailored to the athletes' level of function, expectations, and goals. The timing of interventions also influences the treatment algorithm. A successful outcome can be anticipated when appropriate treatment is rendered.

Velocity, Agility, and Flexibility Performance after Handball Training versus Physical Education Program for Preadolescent Children

The performance on velocity, agility, and flexibility after six months of specific handball training or a mainstream physical education program was examined in participants (handball, n = 51; physical education, n = 70) who engaged in 3 sessions per week (60 min./sesson) including ball-handling exercises, horizontal and vertical jump shots, fast breaks, and several defensive skills. Statistically significant differences were observed between the two groups on velocity, agility, and flexibility with differences favouring the handball group. Handball training could significantly improve préadolescents' physical performance.

The relationship between age and baseball pitching kinematics in professional baseball pitchers

Joint range of motion and physical capacities have been shown to change with age in both throwing athletes and non-athletes. The age of professional baseball pitchers could span from late teens to mid-40s. However, the effects of age on the pitching kinematics among professional baseball pitchers are still unknown. In this study, 67 healthy professional baseball pitchers were tested using a 3D motion analysis system. Their mean age was 23.7+/-3.3 years (range 18.8-34.4). The 12 pitchers more than one standard deviation older than the mean (i.e., older than 27.0 years) were categorized into the older group, and the 10 pitchers more than one standard deviation younger than the mean (i.e., younger than 20.4 years) were defined as the younger group. In all, 18 kinematic variables (14 position and 4 velocity) were calculated, and Student's t-tests were used to compare the variables between the two groups. Six position variables were found to be significantly different between the two groups. At the instant of lead foot contact, the older group had a shorter stride, a more closed pelvis orientation, and a more closed upper trunk orientation. The older group also produced less shoulder external rotation during the arm cocking phase, more lead knee flexion at ball release, and less forward trunk tilt at ball release. Ball velocity and body segment velocity variables showed no significant differences between the two groups. Thus, differences in specific pitching kinematic variables among professional baseball pitchers of different age groups were not associated with significant differences in ball velocities between groups. The current results suggest that both biological changes and technique adaptations occur during the career of a professional baseball pitcher.

Biomechanics and development of the elbow in the young throwing athlete

This article reviews basic concepts in fundamental elbow biomechanics, particularly how they relate to the skeletally immature elbow in throwing athletes. Adult phases of throwing and the forces generated in each phase are compared with the developmental phases of throwing in children. The impact of elevated forces, poor mechanics, and poor coordination are emphasized as they relate to potential areas of injury in the skeletally immature. Finally, concepts in prevention focused on biomechanics are offered.

Athletic injuries of the wrist and hand. Part I: traumatic injuries of the wrist

Hand and wrist injuries in sports are some of the most common injuries reported. This review discusses briefly the causes of hand and wrist injuries in sports and discusses pertinent biomechanical findings regarding the range of motion required in different sports activities. The bulk of the review discusses specific traumatic and overuse injuries to the hand and wrist commonly seen in the athlete. Emphasis is placed on problematic traumatic injuries such as carpal scaphoid fractures and hook of the hamate fractures, as well as ligament injuries to the wrist with regard to diagnosis, treatment, and return to athletic competition.

Upper and lower body strength in relation to underhand pitching speed by experienced and inexperienced pitchers

The relation of legs, arms, shoulders, and grip strength with underhand pitching speed of experienced and inexperienced female pitchers was investigated. For 16 experienced female underhand pitchers and 16 inexperienced women with no softball experience (control group) leg and arm strength were measured using a Hydrafitness exercise machine. Grip strength was measured with a handgrip dynamometer. Underhand throwing speed was measured with a radar gun. Regression analysis showed arm and grip strength correlated with throwing speed (p < or = .05) for the experienced group. For the inexperienced control group, the only correlate of throwing speed was arm strength (p < or = .05). There was a significant difference between the two groups on all measures of strength and ball speed in favor of the experienced group (p < or = .05).

Kinematic and kinetic comparison of baseball pitching among various levels of development

Proper biomechanics help baseball pitchers minimize their risk of injury and maximize performance. However previous studies involved adult pitchers only. In this study, 23 youth, 33 high school, 115 college, and 60 professional baseball pitchers were analyzed. Sixteen kinematic (11 position and five velocity), eight kinetic, and six temporal parameters were calculated and compared among the four levels of competition. Only one of the 11 kinematic position parameters showed significant differences among the four levels, while all five velocity parameters showed significant differences. All eight kinetic parameters increased significantly with competition level. None of the six temporal parameters showed significant differences. Since 16 of the 17 position and temporal parameters showed no significant differences, this study supports the philosophy that a child should be taught 'proper' pitching mechanics for use throughout a career. Kinetic differences observed suggest greater injury risk at higher competition levels. Since adult pitchers did not demonstrate different position or temporal patterns than younger pitchers, increases in joint forces and torques were most likely due to increased strength and muscle mass in the higher level athlete. The greater shoulder and elbow angular velocities produced by high-level pitchers were most likely due to the greater torques they generated during the arm cocking and acceleration phases. The combination of more arm angular velocity and a longer arm resulted in greater linear ball velocity for the higher level pitcher. Thus, it appears that the natural progression for successful pitching is to learn proper mechanics as early as possible, and build strength as the body matures.

Biomechanics of windmill softball pitching with implications about injury mechanisms at the shoulder and elbow

Underhand pitching has received minimal attention in the sports medicine literature. This may be due to the perception that, compared with overhead pitching, the underhand motion creates less stress on the arm, which results in fewer injuries. The purpose of this study was to calculate kinematic and kinetic parameters for the pitching motion used in fast pitch softball. Eight female fast pitch softball pitchers were recorded with a four-camera system (200 Hz). The results indicated that high forces and torques were experienced at the shoulder and elbow during the delivery phase. Peak compressive forces at the elbow and shoulder equal to 70-98% of body weight were produced. Shoulder extension and abduction torques equal to 9-10% of body weight x height were calculated. Elbow flexion torque was exerted to control elbow extension and initiate elbow flexion. The demand on the biceps labrum complex to simultaneously resist glenohumeral distraction and produce elbow flexion makes this structure susceptible to overuse injury.