Hip Range of Motion and Strength and Energy Flow During Windmill Softball Pitching

Fastpitch Softball Injuries: Epidemiology, Biomechanics, and Injury Prevention

PURPOSE OF REVIEW

Fastpitch softball is one of the most popular sports among youth and high school female athletes. Despite some similarities to baseball, key differences between the two sports result in different injury patterns, and there is comparatively less literature describing injury epidemiology in fastpitch softball. The purpose of this review is to describe the epidemiology, biomechanics, and injury prevention efforts in regards to fastpitch softball injury with a particular focus on underhand pitching.

RECENT FINDINGS

The injury rate in softball is relatively low and extended time loss injuries in particular are uncommon. Lower extremity injuries are more common overall in softball, but pitchers more often suffer upper extremity injury. Pitchers account for a relatively small proportion of all injuries recorded, but represent a similarly small subset of team rosters, with most teams carrying only a few pitchers in total. The underhand pitching motion exerts significant glenohumeral distractive forces and high stress across the biceps-labrum complex. Core and lower extremity strengthening play an important role in injury prevention for softball pitchers and position players. Fatigue and number of games pitched are tied to increased strength deficiencies and pain in fastpitch softball pitchers, yet pitch count limits are not employed in any major fastpitch softball leagues. While overall injury incidence is low in fastpitch softball players, the potential for overuse injury in pitchers in particular is noteworthy and not nearly as scrutinized as within the baseball community. Critical longitudinal tracking of softball injuries at varying levels of play would be helpful to better understand the sport's injury risk. There are currently no formal pitch count limits enforced in a majority of fastpitch softball leagues. Core and lower extremity strengthening, pre-season conditioning, and monitoring of pitchers for signs of fatigue may be helpful in injury prevention.

Evaluation of Hip Characteristics in Baseball and Softball Athletes with and Without Throwing Arm Pain

During throwing, the lower extremity assists in the generation and transfer of momentum. Lower extremity stability assists in this transfer by providing a base for distal mobility of the arm segments. This study aimed to determine differences between hip rotational range of motion and strength based on the presence of throwing-arm pain (yes/no) and throwing sport (baseball/softball). We hypothesized those experiencing pain would display decreases in hip range of motion and strength, and that softball players would display greater range of motion than baseball, but less strength based on sex-specific characteristics. Forty-four baseball (13±2 years, 165.2±13.0 cm, 58.5±13.4 kg) and 50 softball players (13±2 years, 160.9±11.2 cm, 62.7±17.9 kg) participated. Multivariate analysis of variance tests (2×2) determined differences in bilateral hip range of motion, total arc of motion, and strength between pain status and sport. There were no significant interactions (>0.05) for pain status and sport on hip range of motion, total arc of motion, and strength. Furthermore, no significant main effects (>0.05) were found for pain status or sport alone on range of motion or strength. Future work should be directed at explaining the effects of hip characteristics on the throwing motion and how it equates to throwing-arm health.

Common Injuries in Female Competitive Softball Players

The popularity of softball is rising among female athletes with more than two million players between the ages of 12 and 18 competing per year. As participation rates increase, the frequency of injuries related to softball is on the rise. Softball injuries can differ from baseball injuries, and only a small amount of current literature focuses exclusively on softball injuries. Orthopaedic surgeons need to be prepared to evaluate, diagnose, and treat common injuries sustained while playing softball. The purpose of this study is to investigate the mechanisms of injury that are commonly encountered by female athletes in competitive fast-pitch softball and review current safety initiatives that have been implemented to aide in injury prevention.

Daily walking kinematic characteristics of the elderly in different residential settings: experimental study on Chinese community-living elderly and long-term nursing home residents

BACKGROUND

Long-term nursing home (NH) care helps NH residents with their daily activities and improves their quality of life, but negatively affects their independent physical activities and increases the risk of dangerous events. Dangerous events in the elderly usually occur in the conversion of walking periods when forward striding has already happened, but the body has not yet entered a completely steady walking.

OBJECTIVES

Compare the gait characteristics in Chinese long-term NH residents and community-living elderly during the walking Transitional Period (TP) and Stabilization Period (SP).

METHODS

32 long-term NH residents and 33 age- and sex-matched community-living elderly were recruited. The 30-Second Chair Stand Test (30-s CST), Timed Up and Go Test (TUGT), and Modified Falls Efficacy Scale (MFES) were used to assess their body function. The Xsens MVN BIOMECH system was used to collect and analyze the gait parameters of participants.

RESULTS

Compared to community-living elderly, NH residents had fewer numbers of 30-s CST, took more time to complete TUGT, and lower MEFS scores. NH residents showed slower gait speed (P < 0.001), less peak hip flexion (P = 0.022) and extension (P = 0.003), knee internal rotation (P = 0.023), and ankle plantarflexion (P = 0.001) and internal rotation (P = 0.007) angles during walking. When walking progressed from TP to SP, NH residents showed increased ankle dorsiflexion (P < 0.001), decreased hip internal rotation (P < 0.001), and community-living elderly had increased hip extension (P = 0.005) angles.

CONCLUSIONS

Chinese long-term NH residents had reduced lower extremities strength and postural balance, and higher fear of falling compared to community-living elderly. Their walking performance also showed high fall risk. Besides, long-term NH residents adopted a distal strategy to propel the body forward, which may be a compensatory measure to compensate for inadequate proximal joint control from forward walking to stable walking, and long-term NH residents have reduced postural stability during this process.

Kinematic Parameters Predictive of Pitch Velocity in Youth to Professional Baseball Pitchers: A Qualitative Systematic Review

Background

Specific kinematic factors have been found to contribute to faster pitch speeds, with poor mechanics leading to injury.

Purpose

To discuss the kinematic parameters that predict faster ball velocity among baseball pitchers.

Study Design

Systematic review.

Methods

Using the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines, the authors utilized the Cochrane Database of Systematic Reviews, PubMed (2008-2019), and OVID/MEDLINE (2008-2019) databases. Eligible articles included those that reported on kinematic factors predictive of ball velocity across youth, high school, collegiate, and professional levels of play. The quality of all included studies was evaluated by 2 reviewers using the Appraisal tool for Cross-Sectional Studies (AXIS). The lack of consistent study design or outcome variables precluded meta-analysis.

Results

A total of 584 studies were identified from the initial search with 12 included in final analysis (930 pitchers in total; 429 [46.1%] youth, 164 [17.6%] high school, 153 [16.5%] collegiate and 184 [19.8%] professional) with mean ball velocity of 71.1 mph (114.4 km/h). The average AXIS score was 16 out of a possible 20. The shoulder played a significant role in the generation of velocity-induced torques. Hip and shoulder separation was associated with a 2.6 ± 0.5 mph (4.1 ± 0.8 km/h) increase in velocity, whereas increased shoulder movement of the nonthrowing arm was negatively correlated with initial ball velocity (r2 = 0.798). Furthermore, hip/shoulder separation, decreased movement of the nonthrowing shoulder, trunk power and timing of maximum trunk rotation, increased contralateral trunk tilt and increased sagittal-plane trunk tilt, and decreased knee flexion at ball release were all associated with higher fastball speeds.

Conclusion

Multiple upper extremity and trunk kinematic parameters affect ball velocity, with significant contributions from the throwing shoulder and trunk, as well as nondominant arm. Understanding kinematic predictors of faster ball velocity can help guide training regimens.

Advancements for the Future: A National Survey of Fastpitch Softball Coaches' Perspectives on Injury Prevention Programming

Background

Approximately 50 percent of softball injuries are the result of overuse or chronic conditions. However, research exploring preventative measures for softball players is limited and usage of injury prevention strategies among softball coaches is unknown.

Hypothesis/Purpose

This survey aimed to investigate if softball coaches are implementing injury prevention programs to reduce injury and improve the performance of their players. The secondary purpose was to identify barriers to the implementation of injury prevention programs. Finally, this survey explored the coaches' knowledge of injury risk factors and their views on design and usage of preventative programs.

Study Design

Descriptive cross-sectional survey.

Methods

A 35-item survey was sent to approximately 14,000 high school and collegiate fastpitch softball coaches throughout the United States. Data were collected over a three-month period with an overall response rate of 1.2%.

Results

Among responding coaches, 45.9% (n=79/172) reported implementing injury prevention programs. Coaches who implement injury prevention strategies most frequently utilize team-based programs (68.8%, n=52/93) compared to group-based (19.0%, n=15/93) or individualized programs (15.2%, n=12/93). Coaches who do not use preventative programming reported that being unsure of what program to perform (53.8%, n=50/93) and not having enough staff (20.4%, n=19/93) were the greatest barriers to implementation. Although over 50% of coaches recognized arm fatigue/overuse (27.9%, n=48/172) and decreased core strength (22.7%, n=39/172) were important risk factors, 36% (n=94/172) "disagree" that softball pitchers should adhere to pitch counts and 90% (n=83/92) believe that preventative programming for pitchers and position players should be similar.

Conclusion

Less than 50 percent of softball coaches implement exercise programs to prevent injury. Limited familiarity with effective program design, inadequate staffing, and inconsistent risk factor awareness are the major contributors to lacking implementation. Collaboration between rehabilitation professionals and softball coaches regarding preventative programming should be considered.

Level of Evidence

Level 3©The Author(s).

Single-Leg Squat and Reported Pain in Collegiate Softball Pitchers

Background

Single-leg squat (SLS) performance is related to altered mechanics related to injury during the windmill softball pitch; however, it is unknown if SLS kinematics differ between softball pitchers with and without upper extremity pain.

Purpose/Hypothesis

The purpose of this study was to compare knee valgus, trunk rotation, trunk lateral flexion, and trunk flexion during an SLS in collegiate softball pitchers with and without self-reported upper extremity pain. It was hypothesized that those who reported upper extremity pain would show increased compensatory trunk and knee kinematics compared with those without pain.

Study Design

Controlled laboratory study.

Methods

A total of 75 collegiate softball players (mean age, 20.4 ± 1.7 years; mean height, 173.3 ± 7.7 cm; mean weight, 79.1 ± 11.6 kg) participated and were placed in pain (n = 20) or no-pain (n = 55) groups. Participants performed an SLS once per side. Kinematic data were collected at 100 Hz using an electromagnetic tracking system. A 2 (pain vs no pain) × 2 (descent vs ascent) × 2 (drive leg vs stride leg) mixed-design multivariate analysis of variance with Wilks lambda distribution was used to determine differences in drive-leg and stride-leg lower body mechanics between the descent and ascent phases of the SLS between the pitchers in the current study with and without pain.

Results

There was no significant effect in the 3-way interaction between upper extremity pain, side, and phase (Λ = 0.960; F[4, 70] = 0.726; P = .577; η² = 0.04). However, there were large effects for the phase × side interaction (Λ = 0.850; P = .021; η² = 0.150). There was a main effect of phase (Λ = 0.283; P < .001; η² = 0.717).

Conclusion

Study findings indicated that SLS mechanics do not differ between collegiate softball pitchers with and without reported upper extremity pain. Drive-leg mechanics showed more stability in the SLS than stride-leg mechanics.

Clinical Relevance

Softball pitchers are at risk of upper extremity injury. It is important to identify mechanisms that may lead to pain in order to mitigate the risk of injury.

Pelvis and Trunk Energy Flow in Collegiate Softball Pitchers With and Without Upper Extremity Pain

BACKGROUND

The softball pitch is a full-body motion, where efficient proximal to distal energy flow through the kinetic chain is said to reduce stress at the upper extremity. Although altered trunk kinematic parameters are associated with upper extremity pain in softball pitchers, further research is needed to determine whether differences exist in proximal energy flow between softball pitchers with and without pain.

HYPOTHESIS/PURPOSE

To examine pelvis and trunk energy flow during the acceleration phase of the pitch in collegiate softball pitchers with and without upper extremity pain. It was hypothesized that those with upper extremity pain would have less energy flowing into the proximal ends of the pelvis and trunk as well as less energy flowing out of the distal ends of the pelvis and trunk during the acceleration phase when compared with pitchers who did not have upper extremity pain.

STUDY DESIGN

Descriptive laboratory study.

METHODS

A total of 54 female National Collegiate Athletic Association Division I softball pitchers (age, 20.2 ± 2.0 years; height, 173.5 ± 6.9 cm; weight, 78.5 ± 11.5 kg) were assigned to pain (n = 17) and pain-free (n = 38) groups. Participants pitched 3 maximal effort rise-balls for a strike, and the average of the 3 trials was used for analysis. Kinematic data were collected at 100 Hz using an electromagnetic tracking system. A segment power analysis was performed to quantify energy flow for the pelvis and trunk. The Mann-Whitney U test was used to compare pelvis and trunk energy flow during the acceleration phase of the pitch as well as pitch velocity between collegiate softball pitchers with and without upper extremity pain.

RESULTS

No significant differences were found between pelvis and trunk energy flow during the acceleration phase or pitch velocity between collegiate softball pitchers with and without upper extremity pain (all P values >.057).

CONCLUSION

Previous research determined that kinematic parameters differ between collegiate pitchers with and without upper extremity pain. However, the current study found no difference in pelvis and trunk energy flow or pitch velocity. Although altered kinematics in collegiate pitchers with upper extremity pain may serve as compensation patterns to maintain pitch velocity and proximal energy flow, future research is needed to confirm this postulation.

CLINICAL RELEVANCE

The lack of energy flow differences between upper extremity pain groups suggests that pitchers may adapt their biomechanics to maintain trunk and pelvis energy flow patterns. Coaches, athletes, and clinicians should know that movement adaptations can allow for maintained performance levels but may result in the presence of pain that may manifest in other deleterious and injury-susceptible biomechanics.

Peak Elbow Flexion Does Not Influence Peak Shoulder Distraction Force or Ball Velocity in NCAA Division I Softball Pitchers

Background:

High shoulder distraction force has been observed in softball pitchers during the acceleration phase (top of the pitch to ball release) of a pitch. Increasing elbow flexion may reduce shoulder forces and the susceptibility to pain by shortening the lever arm of the throwing arm.

Purpose:

To determine the association of peak elbow flexion during the acceleration phase of the pitch with peak shoulder distraction force and ball velocity.

Study Design:

Descriptive laboratory study.

Methods:

A total of 61 female collegiate softball pitchers (mean age, 19.9 ± 1.9 years; mean height, 175.7 ± 5.7 cm; mean weight, 83.6 ± 12.7 kg; 49 right-handed) volunteered for this study. Biomechanical data were collected with a 3-dimensional electromagnetic tracking system while the pitchers threw 3 maximal-effort fastballs at a regulation distance. Peak elbow flexion and peak shoulder distraction force were calculated for the acceleration phase and averaged across the 3 trials. Ball velocity was assessed with a radar gun.

Results:

Simple linear regression analyses indicated that peak elbow flexion did not influence peak shoulder distraction force during the acceleration phase of the pitch (F(1,59) = 2.412; P = .126), with R² = 0.023. Additionally, peak elbow flexion during the acceleration phase of the pitch did not influence ball velocity (F(1,59) = 2.435; P = .124), with R² = 0.023. A bivariate correlation analysis showed a significant association between ball velocity and shoulder distraction force (R² = 0.343; P = .007) in which ball velocity constituted approximately 34% of the variance in shoulder distraction force.

Conclusion:

Peak elbow flexion did not influence ball velocity or peak shoulder distraction force during the acceleration phase of a windmill softball pitch. However, there was a significant and positive relationship between ball velocity and peak shoulder distraction force. These results may indicate that ball velocity and other kinematic variables may be more related to shoulder distraction force than elbow flexion.

Clinical Relevance:

Increasing elbow flexion can shorten the lever arm, but it did not reduce shoulder distraction force or increase ball velocity. Therefore, elbow flexion may be more useful as a description of the pitching style rather than a single measure related to increased performance or the risk of injuries. Future research should continue to examine the relationship between other kinematic parameters with shoulder distraction force.

Segment power analysis of collegiate softball hitting

The primary aim of this investigation was to describe the energy flow through the kinetic chain during softball hitting using a segmental power analysis. Twenty-three NCAA Division I collegiate softball athletes (20.4 ± 1.7 yr; 166.7 ± 22.0 cm; 74.9 ± 15.9 kg) performed three maximum effort swings off a stationary tee placed in the middle of the strike zone. Pelvis, trunk, humerus, forearm and hand segment powers were integrated across four phases of the softball swing (load, stride, acceleration, and follow-through). The load and stride phases had low segment energy inflow and outflow values as well as net segment energy flow for all body segments compared to subsequent phases of the swing. The acceleration phase showed large trunk inflow values relative to the pelvis. There was also descriptively larger front compared to back-side upper extremity inflow. Finally, the follow-through phase showed primarily energy outflow for the upper extremity segments likely attributed to slowing down rotation.

Comparison of Pelvis and Trunk Kinematics Between Youth and Collegiate Windmill Softball Pitchers

Background

The windmill softball pitch is a dynamic sporting movement that places softball pitchers at high risk of injury. Unlike baseball, there is limited research into the mechanical differences between softball pitchers of varying skill levels.

Purpose/Hypothesis

The purpose of this study was to compare pelvis and trunk kinematics between youth and collegiate softball pitchers. It was hypothesized that there would be significant differences in pelvis and trunk kinematics between these 2 groups.

Study Design

Descriptive laboratory study.

Methods

The pelvic and trunk kinematics of 90 softball pitchers were collected during full-effort pitching using a 3-dimensional motion capture system. Participants were grouped based on their age at the time of data collection (35 youth [mean age, 11 ± 1 years]; 55 collegiate [mean age, 20 ± 2 years]). We compared between-group differences in pelvic posterior tilt, lateral tilt, axial rotation, and axial rotation velocity as well as trunk extension, lateral flexion, axial rotation, and axial rotation velocity during the pitching phase between start of pitch and ball release (BR) using 1-dimensional statistical parametric mapping. Statistical significance was determined using Holmes-Šidák stepdown correction-adjusted P values (P ').

Results

Compared with youth pitchers, collegiate pitchers exhibited a more posteriorly tilted pelvis from the moment of start of pitch until 94% of the way between start of pitch and BR (P ' = .002) and a more laterally flexed trunk toward the glove side from the moment of start of pitch until 71% of the way between start of pitch and BR (P ' = .010).

Conclusion

Collegiate pitchers displayed a more posteriorly tilted pelvis and more laterally flexed trunk toward the glove side during the windmill pitching motion when compared with youth pitchers.

Clinical Relevance

These findings add to the growing body of softball research and help elucidate mechanical differences between youth and collegiate softball pitchers.