The throw: biomechanics and acute injury

Gainor, Barry J.; Piotrowski, George; Puhl, James J.; Allen, William C.; Hagen, Robert

doi:10.1177/036354658000800210

Cited by 127 publications

(34 citation statements)

References 4 publications

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“…anterior ligament laxity, increased likelihood of dislocation (Meister, 2000)] may be driven by use of the capsular ligaments to store elastic energy. While these injuries directly result from forelimb positioning necessary to maximize elastic energy storage, it may be possible to protect against such injuries by limiting the frequency of high-speed throwing (Feltner and Dapena, 1986;Fleisig et al, 2011;Fleisig et al, 1996;Gainor et al, 1980;Rizio and Uribe, 2001;Sabick et al, 2004) or wearing mildly restrictive garments (such as a compression shirt) to prevent over rotation. Finally, morphological shifts known to occur in hominins may affect the performance of each of the motions targeted in this study.…”

Section: Discussionmentioning

confidence: 99%

Upper body contributions to power generation during rapid, overhand throwing in humans

Roach

Lieberman

2014

Journal of Experimental Biology

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High-speed and accurate throwing is a distinctive human behavior. Achieving fast projectile speeds during throwing requires a combination of elastic energy storage at the shoulder, as well as the transfer of kinetic energy from proximal body segments to distal segments. However, the biomechanical bases of these mechanisms are not completely understood. We used inverse dynamics analyses of kinematic data from 20 baseball players fitted with four different braces that inhibit specific motions to test a model of power generation at key joints during the throwing motion. We found that most of the work produced during throwing is generated at the hips, and much of this work (combined with smaller contributions from the pectoralis major) is used to load elastic elements in the shoulder and power the rapid acceleration of the projectile. Despite rapid angular velocities at the elbow and wrist, the restrictions confirm that much of the power generated to produce these distal movements comes from larger proximal segments, such as the shoulder and torso. Wrist hyperextension enhances performance only modestly. Together, our data also suggest that heavy reliance on elastic energy storage may help explain some common throwing injuries and can provide further insight into the evolution of the upper body and when our ancestors first developed the ability to produce high-speed throws.KEY WORDS: Throwing, Biomechanics, Elastic energy storage, Kinetic chain, Human evolution INTRODUCTIONThe human forelimb is derived relative to other hominoids and to earlier hominins (Larson, 1993;Larson, 2007). One reason the human shoulder may be so different is selection for humans' unique ability to throw objects overhand with both accuracy and high velocity. Today, most high-speed throwing occurs during sports, but in the past throwing was probably crucial for hunting, defense against predators, and aggressive interactions. Regardless of their purpose, high-speed overhand throws are produced using a stereotypic, whip-like motion involving the whole body.The throw begins with movement of the legs and progresses quickly up the trunk and arm, ending with rapid movement of the throwing hand as the projectile is released. There has been considerable inquiry into how this complex motion generates high projectile velocities, and which joints and joint-specific angular motions are primarily responsible Fleisig et al., 1995;Hirashima et al., 2007;Hirashima et al., 2008;Hong et al., , 1985;Putnam, 1993). Previous work has shown that large angular velocities of torso rotation, shoulder internal rotation, elbow extension and wrist flexion all occur at the moment of release and significantly contribute to projectile speed ( Fig. 1) (Fleisig et al., 1995;Fleisig et al., 1996;Hirashima et al., 2007;Pappas et al., 1985). This study focuses on how these large angular velocities are produced in the upper body. RESEARCH ARTICLEAngular movements are produced when torques act across joints, generating mechanical work and power. Muscles are the source of...

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Section: Discussionmentioning

confidence: 99%

Upper body contributions to power generation during rapid, overhand throwing in humans

Roach

Lieberman

2014

Journal of Experimental Biology

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“…as the arm accelerates, internal rotation of the humerus occurs with such velocity that protective muscle reflexes have been built into the motion. Rotation is accompanied by axial compression which drives the humerus into the glenoid fossa, preventing distraction of the arm and doubling the stress that can be applied to the humerus without fracture (Fleisig et al 1995;Gainor et al 1980). innate mechanisms also protect the elbow.…”

Section: What Causes Childhood Gender Differences In Throwing?mentioning

confidence: 99%

The ontogeny of throwing and striking

Young

2009

Human Ontogenetics

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The ontogeny of throwing and striking R i c h a R d W . Y o u n g r E V i E W abstract humans are the most adept throwers in the animal kingdom. although throwing has been recorded in other primates, it is rare, weak, inaccurate and entails only arm movement. in contrast, human throwing is an explosive act employed from a bipedal stance that involves a complex, exceedingly rapid, full-body movement. This motion generates a pulse of kinetic energy in the legs that is progressively augmented by the pelvis, trunk, arm and hand, where it is transferred to a missile that is launched toward the target with high velocity and accuracy. Linking the study of throwing development in young children with analysis of the adult throwing motion makes it possible to address the question of whether human throwing is an acquired behavior or is based primarily on an inherited motor program. current evidence supports the conclusion that the role of instruction and learning is minimal. human throwing is predominantly the result of an innate motor program which emerges at a very early age in all children without teaching, yields a throwing motion that is the forerunner of the one used by adult athletes, is characterized by a prominent gender difference, and proceeds in some adults to a high level of proficiency. The same conclusions apparently apply also to striking (club-swinging), which employs a similar full-body motion. an explanation for these observations is presented, based upon the concept that throwing and club-swinging prowess provided reproductive advantages during early human evolution.introduction Darwin (1871) was the first to call attention to the remarkable ability of our species to throw with speed and accuracy. "To throw a stone with as true an aim as can a Fuegian in defending himself, or in killing birds," he wrote, "requires the most consummate perfection in the correlated action of the muscles of the hand, arm, and shoulder, not to mention a fine sense of touch" (1871, p. 138). Such behavior is rarely recorded in other primates, and when observed it is ineffective. darwin associated human throwing prowess with a distinctive body structure. The hands and arms could hardly have become perfect enough to have hurled stones and spears with a true aim, he believed, as long as they were habitually used for locomotion, body support, or climbing trees; furthermore, the successful thrower must stand firmly on his feet in an upright, bipedal stance. Today, darwin's conclusions are thoroughly documented. Modern human adults are indeed the most effective throwers by a wide margin, a generalization that can be expanded to include the related behavior of swinging clubs. in their highest development, both motor skills employ a rapid, coordinated sequence of muscle contractions that begins in the legs and traverses the body, progressively accumulating kinetic energy that ultimately is transmitted to the hand, which then projects the missile or club towards a target.is this behavior inherited or learned? is it based upon an innat...

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“…6,9,10 According to the 1989 to 1990 NCAA Injury Surveillance System,12 shoulder injuries have been the most frequently occurring baseball injury every year since 1985, accounting for 19% of the reported injuries. Injuries to the elbow represent 8% of the reported injuries.…”

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confidence: 99%

Eccentric and Concentric Strength of the Shoulder and Arm Musculature in Collegiate Baseball Pitchers

et al. 1995

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Many pitching injuries occur during deceleration of the upper extremity when the muscles of the shoulder and arm are acting eccentrically. Published information regarding eccentric muscular strength in baseball pitchers is nonexistent. The purpose of this study was to assess bilateral isokinetic eccentric and concentric muscular strength of the shoulder's external and internal rotator muscles and the elbow's flexor and extensor muscles in a group of collegiate baseball pitchers (N = 25). Isokinetic strength was assessed at 1.6, 3.7, and 5.2 rad/sec. Our findings indicate that the internal rotator muscles were always stronger than the external rotator muscles and that the concentric and eccentric external-to-internal strength ratios ranged from 62% to 81%. The eccentric strength of the shoulder rotator muscles averaged 114% that of concentric strength. The concentric and eccentric elbow extension-to-flexion strength ratios ranged from 71% to 110%; eccentric strength averaged 33% higher than concentric strength. No differences were noted between dominant and nondominant limbs for any of the strength measures or ratios. Clinically, the findings of this study can serve as a reference during the evaluation, rehabilitation, and conditioning of throwing athletes.

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The throw: biomechanics and acute injury

Cited by 127 publications

References 4 publications

Upper body contributions to power generation during rapid, overhand throwing in humans

Upper body contributions to power generation during rapid, overhand throwing in humans

The ontogeny of throwing and striking

Eccentric and Concentric Strength of the Shoulder and Arm Musculature in Collegiate Baseball Pitchers

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