Timing of ball release in overarm throws affects ball speed in unskilled but not skilled individuals

Impact of Engaging the Nonthrowing Arm on Maximal Ball Velocity From an Overhand Throw With Both the Dominant and Nondominant Arms: A Pilot Study

The overhand throw is a complex whole-body motor skill that is fundamental to many sports and activities. When throwing properly, the momentum generated to complete the movement begins in the lower body and transfers through the trunk to the throwing arm. This proof-of-concept study’s primary purpose was to evaluate the impact of the nonthrowing arm on the ball speed during an overhand throw with both the dominant and nondominant arms. Eighteen participants (age: 20.20 ± 2.90 years, nine women) were divided into two intervention groups: a pulling group taught to engage the nonthrowing arm through a pull toward the body and a nonpulling group taught the overhand throw using a component-based physical education curriculum. Each participant completed 12 total throws, six for each side (dominant and nondominant arm). Ball speed and kinematic data were collected using an eight-camera motion analysis system and were assessed using a pre–post study design. The two groups showed significant improvements pre–post when throwing with both the dominant and nondominant arms. Based on effect size comparisons, engaging the nonthrowing arm makes a meaningful difference in maximal ball velocity.

Applications of the Speed-Accuracy Trade-off and Impulse-Variability Theory for Teaching Ballistic Motor Skills

Bridging the gap between innovative research and teaching is a fundamental necessity for physical education practitioners to promote motor skill development and competency. This requires practitioners to understand, synthesize, and appropriately apply relevant research from different academic domains in their instructional environments. Ballistic motor skills such as kicking, throwing, and striking are fundamentally integrated into many games and sports and provide a foundation for physical activity and fitness for children and adults. Unfortunately, many individuals do not attain a high level of competence in these types of skills by adolescence. The purpose of this review is to integrate theory, pedagogical best practices, and current evidence on studies relating to Fitts' Law's application of the speed-accuracy trade-off and impulse-variability theory to provide an evidence-based framework for promoting effective instructional environments for learning ballistic motor skills.

Can You Hear That Peak? Utilization of Auditory and Visual Feedback at Peak Limb Velocity

PURPOSE

At rest, the central nervous system combines and integrates multisensory cues to yield an optimal percept. When engaging in action, the relative weighing of sensory modalities has been shown to be altered. Because the timing of peak velocity is the critical moment in some goal-directed movements (e.g., overarm throwing), the current study sought to test whether visual and auditory cues are optimally integrated at that specific kinematic marker when it is the critical part of the trajectory.

METHODS

Participants performed an upper-limb movement in which they were required to reach their peak limb velocity when the right index finger intersected a virtual target (i.e., a flinging movement). Brief auditory, visual, or audiovisual feedback (i.e., 20 ms in duration) was provided to participants at peak limb velocity. Performance was assessed primarily through the resultant position of peak limb velocity and the variability of that position.

RESULTS

Relative to when no feedback was provided, auditory feedback significantly reduced the resultant endpoint variability of the finger position at peak limb velocity. However, no such reductions were found for the visual or audiovisual feedback conditions. Further, providing both auditory and visual cues concurrently also failed to yield the theoretically predicted improvements in endpoint variability.

CONCLUSIONS

Overall, the central nervous system can make significant use of an auditory cue but may not optimally integrate a visual and auditory cue at peak limb velocity, when peak velocity is the critical part of the trajectory.

THE LAUNCH WINDOW HYPOTHESIS AND THE SPEED-ACCURACY TRADE-OFF IN BASEBALL THROWING

The speed-accuracy trade-off in throwing has been well described, but its cause is poorly understood. The popular impulse-variability hypothesis lacks relevance to throwing, while the launch window hypothesis has explanatory potential but has not been empirically tested. The current study therefore aimed to quantify the speed-accuracy trade-off and launch window during a throwing task at two different speeds. Nine elite junior baseball players (M age=19.6 yr.; M height=1.80 m; M weight=75.5 kg) threw 10 fastballs at 80 and 100% of maximal throwing speed (MTS) toward a 7 cm target from a distance of 20 m. A 3D motion analysis system measured ball speed and trajectory. A speed-accuracy trade-off occurred, mediated by increased vertical error. This can be attributed to the launch window, which was significantly smaller, particularly its vertical component, during 100% MTS. Maximal throwing speed correlated negatively with launch window size. The launch window hypothesis explained the observed speed-accuracy trade-off, providing a framework within which aspects of technique can be identified and altered to improve performance.

Two types of motor strategy for accurate dart throwing

This study investigated whether expert dart players utilize hand trajectory patterns that can compensate for the inherent variability in their release timing. In this study, we compared the timing error and hand trajectory patterns of expert players with those of novices. Eight experts and eight novices each made 60 dart throws, aiming at the bull’s-eye. The movements of the dart and index finger were captured using seven 480-Hz cameras. The data were interpolated using a cubic spline function and analyzed by the millisecond. The estimated vertical errors on the dartboard were calculated as a time-series by using the state variables of the index finger (position, velocity, and direction of motion). This time-series error represents the hand trajectory pattern. Two variables assessing the performance outcome in the vertical plane and two variables related to the timing control were quantified on the basis of the time-series error. The results revealed two typical types of motor strategies in the expert group. The timing error of some experts was similar to that of novices; however, these experts had a longer window of time in which to release an accurately thrown dart. These subjects selected hand trajectory patterns that could compensate for the timing error. Other experts did not select the complementary hand trajectories, but greatly reduced their error in release timing.

Whole-body and segmental muscle volume are associated with ball velocity in high school baseball pitchers

The aim of the study was to examine the relationship between pitching ball velocity and segmental (trunk, upper arm, forearm, upper leg, and lower leg) and whole-body muscle volume (MV) in high school baseball pitchers. Forty-seven male high school pitchers (40 right-handers and seven left-handers; age, 16.2 ± 0.7 years; stature, 173.6 ± 4.9 cm; mass, 65.0 ± 6.8 kg, years of baseball experience, 7.5 ± 1.8 years; maximum pitching ball velocity, 119.0 ± 9.0 km/hour) participated in the study. Segmental and whole-body MV were measured using segmental bioelectrical impedance analysis. Maximum ball velocity was measured with a sports radar gun. The MV of the dominant arm was significantly larger than the MV of the non-dominant arm (P < 0.001). There was no difference in MV between the dominant and non-dominant legs. Whole-body MV was significantly correlated with ball velocity (r = 0.412, P < 0.01). Trunk MV was not correlated with ball velocity, but the MV for both lower legs, and the dominant upper leg, upper arm, and forearm were significantly correlated with ball velocity (P < 0.05). The results were not affected by age or years of baseball experience. Whole-body and segmental MV are associated with ball velocity in high school baseball pitchers. However, the contribution of the muscle mass on pitching ball velocity is limited, thus other fundamental factors (ie, pitching skill) are also important.

Associations between timing in the baseball pitch and shoulder kinetics, elbow kinetics, and ball speed

BACKGROUND

A baseball pitcher's ability to maximize ball speed while avoiding shoulder and elbow injuries is an important determinant of a successful career. Pitching injuries are attributed to microtrauma brought about by the repetitive stress of high-magnitude shoulder and elbow kinetics.

HYPOTHESIS

Over a number of pitches, variations in timing peak angular velocities of trunk segment rotations will be significantly associated with ball speed and upper extremity kinetic parameters.

STUDY DESIGN

Descriptive laboratory study.

METHODS

Kinematic and kinetic data were derived from 9 to 15 fastball pitches performed by 16 active, healthy collegiate (n = 8) and professional (n = 8) pitchers via 3-dimensional motion capture (240 Hz). Each pitch was decomposed into 4 phases corresponding to the time between peak angular velocities of sequential body segment rotations. Four mixed models were used to evaluate which phases varied significantly in relation to ball speed, peak shoulder proximal force, peak shoulder internal rotation torque, and peak elbow varus torque. Mixed-model parameter coefficient estimates were used to quantify the influence of these variations in timing on ball speed and upper extremity kinetics.

RESULTS

All 4 mixed models were significant (P < .05). The time from stride-foot contact to peak pelvis angular velocity varied significantly in relation to all upper extremity kinetic parameters and ball speed. Increased time in this phase correlated with decreases in all parameters. Decreased ball speed also correlated with increased time between peak upper torso and elbow extension angular velocities. Decreased shoulder proximal force also correlated with increased time between peak pelvis and upper torso angular velocities.

CONCLUSION

There are specific phases that vary in relation to ball speed and upper extremity kinetic parameters, reinforcing the importance of effectively and consistently timing segmental interactions. For the specific interactions that varied significantly, increased phase times were associated with decreased kinetics and ball speed.

CLINICAL RELEVANCE

Although increased time within specific phases correlates with decreases in the magnitude of upper extremity kinetics linked to overuse injuries, it also correlates with decreased ball speed. Based on these findings, it may appear that minimizing the risk of injury (ie, decreased kinetics) and maximizing performance quality (ie, increased ball speed) are incompatible with one another. However, there may be an optimal balance in timing that is effective for satisfying both outcomes.

Skilled throwers use physics to time ball release to the nearest millisecond

Skilled throwers achieve accuracy in overarm throwing by releasing the ball on the handpath with a timing precision as low as 1 ms. It is generally believed that this remarkable ability results from a precisely timed command from the brain that opens the fingers. Alternatively, precise timing of ball release could result from a backforce from the ball that pushes the fingers open. The objective was to test these hypotheses in skilled throwers. Angular positions of the hand and phalanges of the middle finger were recorded with the search-coil technique. In support of the backforce hypothesis, we found that when subjects made a throwing motion without a ball in the hand (i.e., without a backforce), they could not open the fingers rapidly, and they had lost the ability to time finger opening in the 1- to 2-ms range. In addition, relationships were found between the magnitude and timing of hand angular acceleration and finger (joint) extension acceleration. The results indicate that although a central command produced initial hand opening, precise timing of ball release came from a mechanism involving Newtonian mechanics, i.e., hand acceleration produced a backforce from the ball on the fingers that pushed the fingers open. In this mechanism, given the appropriate finger force/stiffness, correction for errors in hand acceleration occurs automatically because hand motion causes finger motion. We propose that skilled throwers achieve ball accuracy by computing finger force/stiffness based on state estimation of hand acceleration and that ball inaccuracy occurs when this computation is imprecise.

Kinematic constraints associated with the acquisition of overarm throwing part I: step and trunk actions

The purposes of this study were to: (a) examine differences within specific kinematic variables and ball velocity associated with developmental component levels of step and trunk action (Roberton & Halverson, 1984), and (b) if the differences in kinematic variables were significantly associated with the differences in component levels, determine potential kinematic constraints associated with skilled throwing acquisition. Results indicated stride length (69.3 %) and time from stride foot contact to ball release (39. 7%) provided substantial contributions to ball velocity (p < .001). All trunk kinematic measures increased significantly with increasing component levels (p < .001). Results suggest that trunk linear and rotational velocities, degree of trunk tilt, time from stride foot contact to ball release, and ball velocity represented potential control parameters and, therefore, constraints on overarm throwing acquisition.

Comparison of kinematics in skilled and unskilled arms of the same recreational baseball players

We examined mechanisms of coordination that enable skilled recreational baseball players to make fast overarm throws with their skilled arm and which are absent or rudimentary in their unskilled arm. Arm segment angular kinematics in three dimensions at 1000 Hz were recorded with the search-coil technique from the arms of eight individuals who on one occasion threw with their skilled right arm and on another with their unskilled left arm. Compared with their unskilled arm, the skilled arm had: a larger angular deceleration of the upper arm in space in the forward horizontal direction; a larger shoulder internal rotation velocity at ball release (unskilled arms had a negative velocity); a period of elbow extension deceleration before ball release; and an increase in wrist velocity with an increase in ball speed. It is suggested that some of these differences in arm kinematics occur because of differences between the skilled and unskilled arms in their ability to control interaction torques (the passive torque at one joint due to motion at adjacent joints). It is proposed that one reason unskilled individuals cannot throw fast is that, unlike their skilled counterparts, they have not developed the coordination mechanisms to effectively exploit interaction torques.