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The Impact of Fatigue on the Kinematics of Collegiate Baseball Pitchers.

Grantham WJ, Byram IR, Meadows MC, Ahmad CS - Orthop J Sports Med (2014)

Bottom Line: Maximum external rotation of the shoulder and elbow height at foot contact decreased over the course of a game.Elbow flexion decreased with greater season pitch counts.Recognition of kinematic alterations may better demonstrate fatigue-related injury risk and may assist injury prevention in addition to standardized limitations of innings and pitches thrown.

View Article: PubMed Central - PubMed

Affiliation: Department of Orthopaedic Surgery, Columbia University Medical Center, New York, New York, USA. ; Department of Orthopaedic Surgery, Vanderbilt University Medical Center, Nashville, Tennessee, USA.

ABSTRACT

Background: Many factors are believed to contribute to throwing injuries in baseball pitchers, in particular overuse and poor throwing mechanics. The impact of fatigue on pitching biomechanics in live-game situations is not well understood.

Hypothesis: Pitchers will demonstrate significant deviation in their pitching motions with increasing levels of fatigue.

Study design: Descriptive laboratory study.

Methods: Eleven National Collegiate Athletic Association (NCAA) Division I collegiate baseball pitchers were filmed in multiple live-game situations throughout a single season using 2 orthogonal high-speed cameras at 120 Hz. The first fastball of each inning and, when available, the fastball subsequent to the 15th and 30th pitch of each inning were recorded and analyzed for 26 kinematic parameters. Pitch count and velocity were recorded. Kinematic differences were assessed for association with pitch count and subjective fatigue measures over the course of each inning and game through the season.

Results: Twenty-six games were recorded. Pitchers had a mean of 97.2 ± 16.1 pitches per start and 1079 ± 251 pitches per collegiate season. Increased hip lean at hand separation, elbow height at foot contact, and hip flexion and shoulder tilt at maximum external rotation were seen in innings lasting longer than 15 pitches. Maximum external rotation of the shoulder and elbow height at foot contact decreased over the course of a game. Hip lean at hand separation and elbow height at foot contact increased over the course of the season. Season pitch count was weakly correlated with increased shoulder external rotation and shoulder alignment at maximum external rotation and with shoulder abduction at ball release. Elbow flexion decreased with greater season pitch counts.

Conclusion: Hip lean, elbow height, and shoulder external rotation were the most sensitive kinematic parameters to inning, game, and season fatigue. Pitch count and fatigue have a significant impact on live-game pitching kinematics.

Clinical relevance: Fatigue likely alters pitching mechanics. Recognition of kinematic alterations may better demonstrate fatigue-related injury risk and may assist injury prevention in addition to standardized limitations of innings and pitches thrown.

No MeSH data available.


Related in: MedlinePlus

Throwing phases. Figure adapted from Werner et al.22 Modified with permission.
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fig2-2325967114537032: Throwing phases. Figure adapted from Werner et al.22 Modified with permission.

Mentions: Each recorded fastball was analyzed using Dartfish software. Twenty-six kinematic points were measured based on similar studies.5,7 The throwing motion was divided into 6 phases: balance point, hand separation, foot contact, maximum external rotation, ball release, and follow through (Figure 2). As noted in Tables 1 through 4, multiple measurements were performed at each of the 6 phases of throwing. Angles were measured using joint centers, with hip and shoulder alignments and hip flexion measured with reference to a horizontal axis (Figures 3 and 4). Of note, elbow height was measured as the distance from the elbow to the shoulder from an orthogonal view. Therefore, any increase in this value was interpreted in a drop in elbow height with reference to the ground, as is often referenced by pitchers and coaches. To determine the precision of the measurements using this methodology, 6 independent trials separated by at least 1 week were performed. Each trial consisted of measuring all 26 parameters of 1 recorded pitch. The standard deviation of linear measurements resulted in a mean of 0.01 m (range, 0.00-0.02 m) and mean of 2.26° (range, 1.19°-5.01°) for angular measures. All measurements were performed by a single member of the research team to avoid interobserver error.


The Impact of Fatigue on the Kinematics of Collegiate Baseball Pitchers.

Grantham WJ, Byram IR, Meadows MC, Ahmad CS - Orthop J Sports Med (2014)

Throwing phases. Figure adapted from Werner et al.22 Modified with permission.
© Copyright Policy - creative-commons
Related In: Results  -  Collection

License 1 - License 2 - License 3
Show All Figures
getmorefigures.php?uid=PMC4555605&req=5

fig2-2325967114537032: Throwing phases. Figure adapted from Werner et al.22 Modified with permission.
Mentions: Each recorded fastball was analyzed using Dartfish software. Twenty-six kinematic points were measured based on similar studies.5,7 The throwing motion was divided into 6 phases: balance point, hand separation, foot contact, maximum external rotation, ball release, and follow through (Figure 2). As noted in Tables 1 through 4, multiple measurements were performed at each of the 6 phases of throwing. Angles were measured using joint centers, with hip and shoulder alignments and hip flexion measured with reference to a horizontal axis (Figures 3 and 4). Of note, elbow height was measured as the distance from the elbow to the shoulder from an orthogonal view. Therefore, any increase in this value was interpreted in a drop in elbow height with reference to the ground, as is often referenced by pitchers and coaches. To determine the precision of the measurements using this methodology, 6 independent trials separated by at least 1 week were performed. Each trial consisted of measuring all 26 parameters of 1 recorded pitch. The standard deviation of linear measurements resulted in a mean of 0.01 m (range, 0.00-0.02 m) and mean of 2.26° (range, 1.19°-5.01°) for angular measures. All measurements were performed by a single member of the research team to avoid interobserver error.

Bottom Line: Maximum external rotation of the shoulder and elbow height at foot contact decreased over the course of a game.Elbow flexion decreased with greater season pitch counts.Recognition of kinematic alterations may better demonstrate fatigue-related injury risk and may assist injury prevention in addition to standardized limitations of innings and pitches thrown.

View Article: PubMed Central - PubMed

Affiliation: Department of Orthopaedic Surgery, Columbia University Medical Center, New York, New York, USA. ; Department of Orthopaedic Surgery, Vanderbilt University Medical Center, Nashville, Tennessee, USA.

ABSTRACT

Background: Many factors are believed to contribute to throwing injuries in baseball pitchers, in particular overuse and poor throwing mechanics. The impact of fatigue on pitching biomechanics in live-game situations is not well understood.

Hypothesis: Pitchers will demonstrate significant deviation in their pitching motions with increasing levels of fatigue.

Study design: Descriptive laboratory study.

Methods: Eleven National Collegiate Athletic Association (NCAA) Division I collegiate baseball pitchers were filmed in multiple live-game situations throughout a single season using 2 orthogonal high-speed cameras at 120 Hz. The first fastball of each inning and, when available, the fastball subsequent to the 15th and 30th pitch of each inning were recorded and analyzed for 26 kinematic parameters. Pitch count and velocity were recorded. Kinematic differences were assessed for association with pitch count and subjective fatigue measures over the course of each inning and game through the season.

Results: Twenty-six games were recorded. Pitchers had a mean of 97.2 ± 16.1 pitches per start and 1079 ± 251 pitches per collegiate season. Increased hip lean at hand separation, elbow height at foot contact, and hip flexion and shoulder tilt at maximum external rotation were seen in innings lasting longer than 15 pitches. Maximum external rotation of the shoulder and elbow height at foot contact decreased over the course of a game. Hip lean at hand separation and elbow height at foot contact increased over the course of the season. Season pitch count was weakly correlated with increased shoulder external rotation and shoulder alignment at maximum external rotation and with shoulder abduction at ball release. Elbow flexion decreased with greater season pitch counts.

Conclusion: Hip lean, elbow height, and shoulder external rotation were the most sensitive kinematic parameters to inning, game, and season fatigue. Pitch count and fatigue have a significant impact on live-game pitching kinematics.

Clinical relevance: Fatigue likely alters pitching mechanics. Recognition of kinematic alterations may better demonstrate fatigue-related injury risk and may assist injury prevention in addition to standardized limitations of innings and pitches thrown.

No MeSH data available.


Related in: MedlinePlus