A biomechanical comparison of baseball pitching from the mound versus the flat ground, focusing on ball velocity and motion of the lower limbs and trunk

Objectives: The incidence of shoulder and elbow overuse injury continues to rise in youth baseball players. Several throwing programs designed to reduce stress on the elbow have been described, but most are not evidence-based. The aim of this study was to compare the kinetics and kinematics between mound and flat-ground pitching at two different distances with the goal of developing evidenced-based injury prevention and recovery guidelines for youth throwers. Methods: Fifteen healthy, high school varsity-level baseball pitchers (mean age 16.7 ± 0.7 yrs; height 182.2 ± 6.2 cm; weight 76.0 ± 9.4 kg;) participated in the study. Players were fitted with a motusBASEBALLTM sensor and sleeve (Motus Global, Rockville Centre, NY), which has been shown to have good reliability and correlation with in-laboratory measures. Each pitcher was asked to pitch 5 fastballs to a catcher under each of the 4 conditions: mound at 60.5 ft (regulation distance), flat ground at 60.5 ft, mound at 50.5 ft, and flat ground at 50.5 ft. For each pitch, the sensor recorded arm speed, arm slot, shoulder rotation, and elbow varus torque. Ball velocity was tracked with a radar gun (Stalker Radar, Richardson, TX). Linear mixed-effects models were used to account for both within and between-subject variability. A multivariable model was used to evaluate the association of mound pitching (vs flat ground), distance (50.5 vs 60.5 ft), and their interaction on each of the following outcomes: arm speed, arm slot, shoulder rotation, elbow varus torque, and ball velocity. Results: There were no statistically significant effects of mound vs flat ground or distance variation on both arm speed or shoulder rotation. Arm slot was significantly higher on pitches from the mound at 60.5 ft [+4.58 (95% CI: 1.26, 7.90), p=0.007]. Elbow varus torque was significantly lower on throws from the mound [-1.88 (95% CI: -3.56, -0.20), p=0.03] and from a longer distance [-2.21 (95% CI: -3.89, -0.53), p=0.01]. Pitches thrown from the mound were significantly faster compared to flat ground at both distances, with throws at 60.5 ft of greater velocity than at 50.5 ft [+1.03 (95% CI: 0.66, 1.40), p<0.001]. Please see the Table for full results. Conclusion: The findings suggest that throwing from the mound may not be higher risk compared to flat ground, contrary to long-standing notions. The lower elbow varus torque and higher arm slot, which has previously been shown to be associated with reduced stress, from throwing from the mound may even indicate a protective effect. Compared to 50.5 ft, there was lower elbow varus torque and faster ball velocity at the longer distance, indicating that elbow stress and ball velocity may not correlate perfectly, and radar guns may not be an appropriate surrogate measure of elbow varus torque. A better understanding of the kinetic and kinematic implications of various throwing programs will allow for designing programs that are based on objective data to achieve the goal of preventing injuries in young baseball players. [Table: see text]

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Effects of Mound Versus Flat-Ground Pitching and Distance on Arm Mechanics and Elbow Torque in High School Pitchers

Orthopaedic Journal of Sports Medicine ◽

10.1177/2325967120969245 ◽

2020 ◽

Vol 8 (12) ◽

pp. 232596712096924

Author(s):

Brittany Dowling ◽

Kathryn D. McElheny ◽

Christopher L. Camp ◽

Daphne I. Ling ◽

Joshua S. Dines

Keyword(s):

High School ◽

Mixed Effects Models ◽

Multivariable Model ◽

Linear Mixed Effects ◽

Study Results ◽

Ball Velocity ◽

Surrogate Measure ◽

Baseball Pitchers ◽

The Impact ◽

Flat Ground

Background: Although the monitoring of a pitcher’s throwing arm workload has become a hot topic in both research and the pitching world, the impact of mound height and distance still remains unclear. Purpose: To compare the kinetics and kinematics between pitches from a mound and flat ground at 2 different distances. Study Design: Descriptive laboratory study. Methods: A total of 21 healthy high school varsity baseball pitchers (age, 16.2 ± 1.3 years; weight, 73.6 ± 11.0 kg; height, 181.3 ± 6.4 cm) participated in this study. Players were fitted with a motusBASEBALL sensor and sleeve. Each pitcher was instructed to pitch 5 fastballs under 4 conditions: mound at 60.5 ft (regulation distance), flat ground at 60.5 ft, mound at 50.5 ft, and flat ground at 50.5 ft. Linear mixed-effects models were used to account for both intra- and interplayer variability. A multivariable model was used to evaluate the association of mound pitching, flat-ground pitching, and their distances (50.5 ft and 60.5 ft), and their interaction to arm speed, arm slot, arm rotation, elbow varus torque, and ball velocity. Results: There were no statistically significant effects of mound, flat-ground, or distance variation on arm speed or shoulder rotation. Arm slot was significantly higher (+3.0°; P = .02) on pitches from the mound at 60.5 ft compared with 50.5 ft. Elbow varus torque was lower (–1.5 N·m; P = .02) on mound pitches at 60.5 ft compared with 50.5 ft. Pitches thrown from the mound displayed significantly faster ball velocity compared with flat-ground pitches at both distances ( P < .01 for both), with pitches at 60.5 ft having higher velocity (+0.7 m/s; P < .01). Conclusion: Contrary to long-standing notions, the study results suggest that pitching from the mound does not significantly increase stress on the elbow compared with flat-ground pitching. Lower elbow varus torque and faster ball velocity at the regulation distance compared with the reduced distance indicate that elbow stress and ball velocity may not correlate perfectly, and radar guns may not be an appropriate surrogate measure of elbow varus torque. Clinical Relevance: A better understanding of the kinetic and kinematic implications of various throwing programs will allow for the designing of programs that are driven by objective data with aims directed toward injury prevention and rehabilitation in baseball pitchers.

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Biomechanical Analysis of Weighted-Ball Exercises for Baseball Pitchers

Sports Health A Multidisciplinary Approach ◽

10.1177/1941738116679816 ◽

2016 ◽

Vol 9 (3) ◽

pp. 210-215 ◽

Cited By ~ 19

Author(s):

Glenn S. Fleisig ◽

Alek Z. Diffendaffer ◽

Kyle T. Aune ◽

Brett Ivey ◽

Walter A. Laughlin

Keyword(s):

Repeated Measures ◽

Rotation Velocity ◽

Elbow Flexion ◽

Biomechanical Analysis ◽

Joint Kinetics ◽

Ball Velocity ◽

Baseball Pitchers ◽

Kinematics And Kinetics ◽

Flat Ground ◽

Ball Mass

Background: Weighted-ball throwing programs are commonly used in training baseball pitchers to increase ball velocity. The purpose of this study was to compare kinematics and kinetics among weighted-ball exercises with values from standard pitching (ie, pitching standard 5-oz baseballs from a mound). Hypothesis: Ball and arm velocities would be greater with lighter balls and joint kinetics would be greater with heavier balls. Study Design: Controlled laboratory study. Methods: Twenty-five high school and collegiate baseball pitchers experienced with weighted-ball throwing were tested with an automated motion capture system. Each participant performed 3 trials of 10 different exercises: pitching 4-, 5-, 6-, and 7-oz baseballs from a mound; flat-ground crow hop throws with 4-, 5-, 6-, and 7-oz baseballs; and flat-ground hold exercises with 14- and 32-oz balls. Twenty-six biomechanical parameters were computed for each trial. Data among the 10 exercises were compared with repeated measures analysis of variance and post hoc paired t tests against the standard pitching data. Results: Ball velocity increased as ball mass decreased. There were no differences in arm and trunk velocities between throwing a standard baseball and an underweight baseball (4 oz), while arm and trunk velocities steadily decreased as ball weight increased from 5 to 32 oz. Compared with values pitching from a mound, velocities of the pelvis, shoulder, and ball were increased for flat-ground throws. In general, as ball mass increased arm torques and forces decreased; the exception was elbow flexion torque, which was significantly greater for the flat-ground holds. There were significant differences in body positions when pitching on the mound, flat-ground throws, and holds. Conclusions: While ball velocity was greatest throwing underweight baseballs, results from the study did not support the rest of the hypothesis. Kinematics and kinetics were similar between underweight and standard baseballs, while overweight balls correlated with decreased arm forces, torques, and velocities. Increased ball velocity and joint velocities were produced with crow hop throws, likely because of running forward while throwing. Clinical Relevance: As pitching slightly underweight and overweight baseballs produces variations in kinematics without increased arm kinetics, these exercises seem reasonable for training pitchers. As flat-ground throwing produces increased shoulder internal rotation velocity and elbow varus torque, these exercises may be beneficial but may also be stressful and risky. Flat-ground holds with heavy balls should not be viewed as enhancing pitching biomechanics, but rather as hybrid exercises between throwing and resistance training.

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A Biomechanical Comparison of Pitching From a Mound Versus Flat Ground in Adolescent Baseball Pitchers

Sports Health A Multidisciplinary Approach ◽

10.1177/1941738113502918 ◽

2013 ◽

Vol 5 (6) ◽

pp. 530-536 ◽

Cited By ~ 17

Author(s):

Carl W. Nissen ◽

Matthew Solomito ◽

Erin Garibay ◽

Sylvia Õunpuu ◽

Melany Westwell

Keyword(s):

Baseball Pitchers ◽

Biomechanical Comparison ◽

Flat Ground

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A Lower Limb Prosthesis Haptic Feedback System for Stair Descent

2017 Design of Medical Devices Conference ◽

10.1115/dmd2017-3409 ◽

2017 ◽

Cited By ~ 2

Author(s):

Astrini Sie ◽

Jonathan Realmuto ◽

Eric Rombokas

Keyword(s):

Lower Limb ◽

Haptic Feedback ◽

The Body ◽

Lower Limbs ◽

Prosthetic Limbs ◽

Stair Descent ◽

Lower Limb Prosthesis ◽

Limb Prosthesis ◽

Flat Ground ◽

Lower Limb Prostheses

Though there are a variety of prosthetic limbs that address the motor deficits associated with amputation, there has been relatively little progress in restoring sensation. Prosthetic limbs provide little direct sensory feedback of the forces they encounter in the environment, but “closing the loop” between sensation and action can make a great difference in performance [1]. For users of lower limb prostheses, stair descent is a difficult and dangerous task. The difficulty in stair descent can be attributed to three different factors: 1) Absence of tactile and haptic sensations at the bottom of the foot. Although force on the prosthetic socket provides some haptic feedback of the terrain being stepped on, this feedback does not provide information on the location of the staircase edge. 2) Insufficient ankle flexion of lower limb prostheses. Dorsiflexion of the physiological ankle during stair descent is about 27°. Even prostheses that provide active dorsiflexion provide less than this number, and regular prostheses provide almost no ankle dorsiflexion. The first two factors are analogous to the sensation of stair descent for someone without amputation wearing ski boots. 3) Prosthetic feet are optimized for flat-ground walking, offering undesirable energy storage at ankle flexion and energy return at toe-off. This can result in unwanted extra energy at the end of stance phase, propelling the user forward down the stairs. Most lower limb prosthesis designs focus on flat ground walking, but there has been less progress in addressing the challenges of stair descent. One technique that users of prosthetic lower limbs can use for addressing these challenges is to employ an “overhanging toe” foot placement strategy. Under this strategy, the edge of the staircase is used as a pivot point for the foot to roll over the stair. This reduces the need for ankle flexion by allowing the knee and hip to compensate, and avoids storing energy in the prosthetic spring. This strategy is dynamic, and requires the user to know the amount of toe overhang to adjust the movement of the rest of the body. Most haptic devices built to assist individuals wearing prostheses focus on upper extremity tasks [2–4] or standing and walking [5,6]. Whereas previous lower limb sensory replacement systems have targeted standing measures, here we focus on stair descent. The system provides cues of the stair edge location via vibrotactile stimulations on the thigh.

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A Biomechanical Comparison of a Limited Open and Standard Open Technique for Achilles Tendon Rupture Repair

Foot & Ankle Orthopaedics ◽

10.1177/2473011417s000156 ◽

2017 ◽

Vol 2 (3) ◽

pp. 2473011417S0001

Author(s):

Robert Dekker ◽

Charles Qin ◽

Cort Lawton ◽

Muturi Muriuki ◽

Robert Havey ◽

...

Keyword(s):

Soft Tissue ◽

Achilles Tendon ◽

Open Repair ◽

Achilles Tendon Rupture ◽

Testing Machine ◽

Tendon Repair ◽

Lower Limbs ◽

Gap Formation ◽

Load To Failure ◽

Biomechanical Comparison

Category: Basic Sciences/Biologics, Sports Introduction/Purpose: The drive to reduce soft tissue complications after Achilles tendon repair has led to increased interest in less invasive techniques. The PARS Achilles Jig System is one option that has gained popularity as an alternative to open repair. For many surgeons, standard open repair consists of a Krackow locking-loop technique. We compared the load to failure of a limited open and open Krackow technique for repair of Achilles tendon ruptures. Methods: Nine pairs of human cadaver lower limbs were randomized to undergo either a Krackow locking loop repair with epitendinous weave or a PARS Achilles Jig System Repair. Specimen were loaded to failure on a servo-hydraulic material testing machine. From load- displacement curves, initial linear stiffness, load to failure, and work to failure were calculated. Results: The average load to failure for Krackow repair (353.8 ± 88.8 N) and PARS repair (313.3 ± 99.9 N) was not statistically different (p = .38). The average work to failure for open repair (6.4 ± 2.3 J) and PARS repair (6.3 ± 3.5 J) was also not statistically different (p = .904). Mean initial linear stiffness of the Krackow repair (17.8 ± 5.4 N/mm) was significantly greater than the PARS repair (11.8 ± 2.5 N/mm) (p = .011). The predominant location of failure for Krackow repair was at the suture itself. In contrast, the PARS repair predominantly failed at the suture-tendon interface. Conclusion: The results suggest no difference between the Krackow and PARS repairs in terms of ultimate strength or work to failure. The Krackow repair demonstrated a higher initial linear stiffness than the PARS, which may imply a greater ability to withstand gap formation. With less devitalization to surrounding soft tissue and equal repair strength, the PARS system should be considered a favourable option for repair of ruptured Achilles tendons.

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Relationships Between Olympic Weightlifting Exercises, Peak Power of the Upper and Lower Limb, Muscle Volume and Throwing Ball Velocity in Elite Male Handball Players

Sportverletzung · Sportschaden ◽

10.1055/a-0625-8705 ◽

2018 ◽

Vol 33 (02) ◽

pp. 104-112 ◽

Cited By ~ 2

Author(s):

Souhail Hermassi ◽

Karl Stefan Delank ◽

Georg Fieseler ◽

Thomas Bartels ◽

Mohamed Souhaiel Chelly ◽

...

Keyword(s):

Upper Limb ◽

Lower Limb ◽

Peak Power ◽

Muscle Volume ◽

Lower Limbs ◽

Lower Limb Muscle ◽

Limb Muscle ◽

Absolute Power ◽

Ball Velocity ◽

Force Velocity

Abstract Background This study aimed to investigate relationships between peak power (PP) as measured by upper limb (PPUL) and lower limb (PPLL) force velocity tests, maximal upper limb force assessed by clean and jerk (1RMCJ) and snatch (1RMSE) exercises, estimates of local muscle volume and throwing ball velocity. Methods Thirty elite male handball players volunteered for the investigation (age: 20.3 ± 2.1 years; body mass: 82.5 ± 10.5 kg; height: 1.85 ± 0,07 %; body fat: 13.1 ± 2.1 %). Lower and upper limb force velocity tests were performed on appropriately modified forms of a Monark cycle ergometer with measurement of PPUL and PPLL, and the corresponding respective maximal forces (F0UL and F0LL) and velocities (V0UL and V0LL). Snatched (SN) and clean and jerk (CJ) exercises were performed to one repetition maximum (1RM). Handball throwing velocity was measured with jump shot (JS) without run-up (TW) and 3 steps shot (T3 step). Muscle volumes of the upper and lower limbs were estimated with a standard anthropometric kit. Results The 1RM CJ proved to be the most important predictor for throwing velocity. All types of throwing showed a high correlation with this parameter (JS: r = 0.75; TW: r = 0.62; T3 step: r = 0.66). The highest relation was detected between jump shot and 1RM snatch technique (r = 0.82). The PPUL muscle volume correlated highly with PPUL absolute power (r = 0.70). In contrast, we did not find any comparable relations for the lower limb (muscle volume vs. PPUL absolute power: r = 0.07). Conclusions Our results highlight the contribution of both lower and upper limbs to handball throwing velocity, suggesting the need for coaches to include upper and lower limb strength weightlifting exercises and power programs when improving the throwing velocity of handball players.

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Biomechanical Comparison of the Track Start and the Modified One-Handed Track Start in Competitive Swimming: An Intervention Study

Journal of Applied Biomechanics ◽

10.1123/jab.24.4.307 ◽

2008 ◽

Vol 24 (4) ◽

pp. 307-315 ◽

Cited By ~ 18

Author(s):

H. Galbraith ◽

J. Scurr ◽

C. Hencken ◽

L. Wood ◽

P. Graham-Smith

Keyword(s):

Intervention Group ◽

Force Plate ◽

Flight Time ◽

Horizontal Velocity ◽

Lower Limbs ◽

Control Group ◽

Vertical Force ◽

Horizontal Force ◽

Competitive Swimming ◽

Biomechanical Comparison

This study compared the conventional track and a new one-handed track start in elite age group swimmers to determine if the new technique had biomechanical implications on dive performance. Five male and seven female GB national qualifiers participated (mean ± SD: age 16.7 ± 1.9 years, stretched stature 1.76 ± 0.8 m, body mass 67.4 ± 7.9 kg) and were assigned to a control group (n = 6) or an intervention group (n = 6) that learned the new one-handed dive technique. All swimmers underwent a 4-week intervention comprising 12 ± 3 thirty-minute training sessions. Video cameras synchronized with an audible signal and timing suite captured temporal and kinematic data. A portable force plate and load cell handrail mounted to a swim starting block collected force data over 3 trials of each technique. A MANCOVA identified Block Time (BT), Flight Time (FT), Peak Horizontal Force of the lower limbs (PHF) and Horizontal Velocity at Take-off (Vx) as covariates. During the 10-m swim trial, significant differences were found in Time to 10 m (TT10m), Total Time (TT), Peak Vertical Force (PVF), Flight Distance (FD), and Horizontal Velocity at Take-off (Vx) (p < .05). Results indicated that the conventional track start method was faster over 10 m, and therefore may be seen as a superior start after a short intervention. During training, swimmers and coaches should focus on the most statistically significant dive performance variables: peak horizontal force and velocity at take-off, block and flight time.

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