Athletic Movements Research Articles

CSM 2010 Sports Physical Therapy Section Platform Presentations (Abstracts SPL1-SPL27)

CSM 2010 Sports Physical Therapy Section Platform Presentations (Abstracts SPL1-SPL27)

Limitations of Functionally Determined Joint Centers for the Analysis of Athletic Human Movement: A Case Study of the Upper Limb

Much research is ongoing into improving the accuracy of functional algorithms to determine joint centers (JC), but there has been limited testing using human movement data. This paper is in three parts: Part 1, errors in determining JCs from real human movement data using the SCoRE method; Part 2, variability of marker combinations during a punch; Part 3, variability in the JC due to reconstruction. Results indicate determining the JC of the shoulder or elbow with a triad of markers per segment with an accuracy greater than 20 mm is unlikely. Part 2 suggests conducting a pilot study with abundant markers to obtain triads, which are most stable due to differences of 300-400% in variability between triads. Variability due to the choice of reference frame for reconstruction during the punch ranged from 2.5 to 13.8 mm for the shoulder and 1.5 to 21.1 mm for the elbow. It would appear more pertinent to enhance the practical methods in situ than to further improve theoretical accuracy of functional methods.

Injuries and Medical Issues in Synchronized Olympic Sports

Spectators of the Olympic Games can enjoy a wide variety of sports, including strength, team, timed, endurance, and artistic sports. In the Olympic program, there are two synchronized events: synchronized diving and synchronized swimming. The precision of the synchronization of the athlete's movements and skills is an added feature of entertainment. Synchronized athletes have additional training requirements to perfect the synchronization of their skills. The physical demands on the athlete from the repetition of training required for the perfection of synchronization result in injuries unique to these sports. Although both traumatic and overuse injuries occur, overuse injuries are more common. As these disciplines are artistic, judged sports, these athletes also are susceptible to eating disorders and the female athlete triad. This article reviews the training regimen of these athletes and outlines the injuries and health concerns that are common in the synchronized sports.

Longitudinal evaluation of Journal of Athletic Training author credentials: implications for future research engagement in athletic training.

To employ retrospective trend analysis in an attempt to provide a layered description of the relative contribution (per credential) of clinical athletic trainers (those without terminal degrees) to authoring scientific literature in the Journal of Athletic Training (JAT). From these data, our secondary purpose was to evaluate trends relative to changes in journal policy and increased educational rigor or professional limitations over the past decade, discussing how they may affect the potential for clinical athletic trainers to contribute to JAT. Exploratory study design with trend analysis. Data collection and analysis included a trend evaluation of the credentials of clinical athletic trainer authors in JAT and the teams (by credential) of authorship to determine the credentials of authors who published in JAT. Longitudinal tabulation of JAT author credentials from 1995 through 2007. We noted increases in the absolute number of research articles per volume and the number of authors per article and a decrease in the relative percentage of authors who were athletic trainers. The results also suggested that the bachelor of science degree (BS-ATC, representative of clinical athletic trainers without advanced degrees) and Doctor of Medicine (MD) credential may be underrepresented in JAT authorship. Postgraduate research training may facilitate scientific article contribution by athletic trainers. Continued evolution in the athletic training evidence-based medicine movement should foster research-based mentorship during education. Cultivating collaborations between clinical athletic trainers and research teams may also promote outcomes assessment trials, which will benefit athletic training practices.

Improved Muscle Activation In Performing A Functional Lunge Versus A Traditional Squat

The back squat is a common exercise for performance strength training and rehabilitation. Contrary to common clinical practice, variation in stance width during the squat has not shown to affect the isolation of quadriceps musculature. In addition to the stance width, squat depth has also been a focus of debate in muscle activation. Today, many practitioners are focusing on more functional activities and it is often questioned if the squat, especially to greater depths is truly a functional exercise. PURPOSE: The purpose was to examine the muscle activation at three different squat depths and the body weight walking lunge. METHODS: Eight healthy, female intercollegiate athletes (mean age 20.8 + 3.9 y; mean height, 177.8 + 10.9 cm; mean mass, 67.3 + 9.9 kg) participated. Electromyographic (EMG) data were collected on the following muscles: medial hamstring (semimembranosus and semitendinosus), biceps femoris, gluteus medius, and gluteus maximus while participants performed the three different squat depths and a body weight walking lunge. RESULTS: Kruskal-Wallis test revealed a significant main effect for exercise type on the rectus femoris (χ2=15.706, p=0.001); vastus medialis oblique (χ2=8.767, p=0.03); vastus lateralis (χ2=15.169, p=0.002); medial hamstrings (χ2=8.775, p=0.03); biceps femoris (χ2=14.258, p=0.003); and gluteus medius (χ2=10.387, p=0.02). Exercise type did not have a main affect on gluteus maximus muscle activity (p=0.05). The results demonstrated that the total muscle activation of the squat depths were not greater than that of the walking lunge. It was revealed that the walking lunge did indeed produce more activation in the majority of all muscles analyzed, except rectus femoris, when compared to the three squat depths. CONCLUSIONS: By training athletes in the walking lunge they can obtain the same results of that of squat to 90 training. Furthermore, the lunge allows athlete to be in a more functional position. From the basic lunge position of the knees flexed to 90 degrees we can begin to train explosive recovery moves which would transfer over to competition. Ideally, athletes should be training their kinetic chain fluidly and dynamically, the more dynamic the activity the more fluid the athlete's movement and posture will be in competition.

Alterations in Knee Joint Laxity During the Menstrual Cycle in Healthy Women Leads to Increases in Joint Loads During Selected Athletic Movements

Background It has been speculated that the hormonal cycle may be correlated with higher incidence of ACL injury in female athletes, but results have been very contradictory. Hypothesis Knee joint loads are influenced by knee joint laxity (KJL) during the menstrual cycle. Study Design Controlled laboratory study. Methods Serum samples and KJL were assessed at the follicular, ovulation, and luteal phases in 26 women. Knee joint mechanics (angle, moment, and impulse) were measured and compared at the same intervals. Each of the 26 subjects had a value for knee laxity at each of the 3 phases of their cycle, and these were ordered and designated low, medium, and high for that subject. Knee joint mechanics were then compared between low, medium, and high laxity. Results No significant differences in knee joint mechanics were found across the menstrual cycle (no phase effect). However, an increase in KJL was associated with higher knee joint loads during movement (laxity effect). A 1.3-mm increase in KJL resulted in an increase of approximately 30% in adduction impulse in a cutting maneuver, an increase of approximately 20% in knee adduction moment, and a 20% to 45% increase in external rotation loads during a jumping and stopping task (P < .05). Conclusion Changes in KJL during the menstrual cycle do change knee joint loading during movements. Clinical Relevance Our findings will be beneficial for researchers in the development of more effective ACL injury prevention programs.

Closed-Kinetic Chain Upper-Body Training Improves Throwing Performance of NCAA Division I Softball Players

Closed-kinetic chain resistance training (CKCRT) of the lower body is superior to open-kinetic chain resistance training (OKCRT) to improve performance parameters (e.g., vertical jump), but the effects of upper-body CKCRT on throwing performance remain unknown. This study compared shoulder strength, power, and throwing velocity changes in athletes training the upper body exclusively with either CKCRT (using a system of ropes and slings) or OKCRT. Fourteen female National Collegiate Athletic Association Division I softball player volunteers were blocked and randomly placed into two groups: CKCRT and OKCRT. Blocking ensured the same number of veteran players and rookies in each training group. Training occurred three times weekly for 12 weeks during the team's supervised off-season program. Olympic, lower-body, core training, and upper-body intensity and volume in OKCRT and CKCRT were equalized between groups. Criterion variables pre- and posttraining included throwing velocity, bench press one-repetition maximum (1RM), dynamic single-leg balance, and isokinetic peak torque and power (PWR) (at 180 degrees x s(-1)) for shoulder flexion, extension, internal rotation, and external rotation (ER). The CKCRT group significantly improved throwing velocity by 2.0 mph (3.4%, p < 0.05), and the OKCRT group improved 0.3 mph (0.5%, NS). A significant interaction was observed (p < 0.05). The CKCRT group improved its 1RM bench press to the same degree (1.9 kg) as the OKCRT group (p < 0.05 within each group). The CKCRT group improved all measures of shoulder strength and power, whereas OKCRT conferred little change in shoulder torque and power scores. Although throwing is an open-chain movement, adaptations from CKCRT may confer benefits to subsequent performance. Strength coaches can incorporate upper-body CKCRT without sacrificing gains in maximal strength or performance criteria associated with an athletic open-chain movement such as throwing.

Research Retreat IV: ACL Injuries—The Gender Bias

In April 2008, more than 80 attendees from across the United States and Canada participated in the fourth research retreat focused on the gender bias in anterior cruciate ligament (ACL) injury. The retreat was cofounded by Irene Davis, PhD, PT, and Mary Lloyd Ireland, MD, who hosted the 3 previous research retreats in Lexington, Kentucky, in April of 2001, 2003, and 2006. In the first year (2001), a consensus document of what we know, don't know, and still need to know related to this problem was developed.1 Each subsequent retreat has revisited and updated the previous consensus statement as new evidence has emerged.2,3 Over the past 6 years, the number of attendees has grown, and the retreats have attracted some of the foremost nationally and internationally known clinicians and scientists with a common interest in ACL injury. We were pleased to continue this important work by hosting Research Retreat IV in Greensboro, North Carolina.The meeting featured an opening presentation from ACL Retreat cofounder Mary Lloyd Ireland, MD; invited keynote presentations by Scott McLean, PhD, and Bruce Beynnon, PhD — expert scientists well known for their research into factors associated with the gender bias in ACL injury; and 31 fifteen-minute podium presentations of recently completed research relating to the gender bias in ACL injuries. The opening presentation set the stage for the meeting by providing a historical perspective of what research has taught us about the ACL injury gender bias over the past 20 years, and the keynote presentations focused on the current knowledge and theories associated with neuromuscular, biomechanical, anatomical, and hormonal risk factors. The podium presentations were organized into thematic sessions centered on sagittal-plane landing mechanics, sex comparisons in landing and cutting, fatigue and perturbation studies in landing and cutting, anatomical and hormonal factors, and risk factor screening and prevention. Significant time was provided for group discussion after each keynote and each group of podium presentations. At the conclusion of the meeting, participants revisited and updated the consensus statement from the 2006 retreat.2 Following are the consensus statement, keynote presentation summaries, and abstracts organized by topic and presentation order.

Is there a “neural efficiency” in athletes? A high-resolution EEG study

“Neural efficiency” hypothesis posits that cortical activity is spatially focused in experts. Here we tested the hypothesis that compared to non-athletes, elite athletes are characterized by a reduced cortical activation during visuo-motor tasks related to the field of expertise, as a function of movement side. EEG data (56 channels; EB-Neuro) were continuously recorded in the following right-handed subjects: 11 non-athletes, 11 elite fencing athletes, and 11 elite karate athletes. During the EEG recordings, they observed pictures with fencing and karate attacks, and had to quickly click a right (left) keyboard button for the attacks at right (left) monitor side. The EEG data were averaged with respect to the movement onset, and were spatially enhanced by surface Laplacian estimation. The potentials related to the preparation (readiness potential) and initiation (motor potential) of the movements were measured. For the right movement, the potentials overlying supplementary motor and contralateral sensorimotor areas were higher in amplitude in the non-athletes than in the elite karate and fencing athletes. Furthermore, the amplitude of the motor potential over ipsilateral sensorimotor area was higher in the elite karate than fencing athletes, and its distribution over bilateral sensorimotor areas was less asymmetrical in the karate than in the other two groups. For the left movement, these potentials showed no difference between the groups. The present results suggest that “neural efficiency” hypothesis does not fully account for the organization of motor systems in elite athletes. “Neural efficiency” would depend on several factors including side of the movement, hemisphere, and kind of athletes.

Effects of Three Types of Resisted Sprint Training Devices on the Kinematics of Sprinting at Maximum Velocity

Resisted sprint running is a common training method for improving sprint-specific strength. For maximum specificity of training, the athlete's movement patterns during the training exercise should closely resemble those used when performing the sport. The purpose of this study was to compare the kinematics of sprinting at maximum velocity to the kinematics of sprinting when using three of types of resisted sprint training devices (sled, parachute, and weight belt). Eleven men and 7 women participated in the study. Flying sprints greater than 30 m were recorded by video and digitized with the use of biomechanical analysis software. The test conditions were compared using a 2-way analysis of variance with a post-hoc Tukey test of honestly significant differences. We found that the 3 types of resisted sprint training devices are appropriate devices for training the maximum velocity phase in sprinting. These devices exerted a substantial overload on the athlete, as indicated by reductions in stride length and running velocity, but induced only minor changes in the athlete's running technique. When training with resisted sprint training devices, the coach should use a high resistance so that the athlete experiences a large training stimulus, but not so high that the device induces substantial changes in sprinting technique. We recommend using a video overlay system to visually compare the movement patterns of the athlete in unloaded sprinting to sprinting with the training device. In particular, the coach should look for changes in the athlete's forward lean and changes in the angles of the support leg during the ground contact phase of the stride.

The natural history and management of hamstring injuries

Hamstring injuries in sport can be debilitating. The anatomical complexity of this muscle makes uniform assessment of injury epidemiology difficult and insures that post-injury management strategies must be individually focused. This article reviews the anatomy of the hamstring, its role in athletic movement, common mechanisms of injury, and management guidelines with the goal of return into sporting activity in mind.

Why think?: evolution and the rational mind

In a world where natural selection has shaped adaptations of astonishing ingenuity, what is the scope and unique power of rational thinking? In this short but wide-ranging book, philosopher Ronald de Sousa looks at the twin set of issues surrounding the power of natural selection to mimic rational design, and rational thinking as itself a product of natural selection. While we commonly deem ourselves superior to other species, the logic of natural selection should not lead us to expect that nature does everything for the best. Similarly, rational action does not always promote the best possible outcomes. So what is the difference? Is the pursuit of rationality actually an effective strategy? Part of the answer lies in language, including mathematics and science. Language is the most striking device by which we have made ourselves smarter than our nearest primate cousins. Sometimes the purely instinctual responses we share with other animals put explicit reasoning to shame: the movements of a trained athlete are faster and more accurate than anything she could explicitly calculate. Language, however, with its power to abstract from concrete experience and to range over all aspects of nature, enables breathtakingly precise calculations, which have taken us to the moon and beyond. Most importantly, however, language enables us to formulate an endless multiplicity of values, in potential conflict with one another as well as with instinctual imperatives. In short, this sophisticated and entertaining book shows how our rationality and our irrationality are inextricably intertwined. Ranging over a wide array of evidence, it explores the true ramifications of being human in the natural world.

Validation of an integrated experimental set-up for kinetic and kinematic three-dimensional analyses in a training environment

Biomechanical analyses using synchronized tools {electromyography (EMG), motion capture, force sensors, force platform, and digital camera] are classically performed in a laboratory environment that could influence the performance. We present a system for studying the running sprint start that synchronizes motion capture, EMG, and ground reaction force data. To maximize motion capture (Vicon 612 with six cameras), a special dim environment was created in the stadium. “Classical” tools were combined with “purpose-built” tools intended to analyse the different aspects of movement. For example, a synchronization system was built to create a common time-base for all data recordings and a portable EMG system was synchronized by a cable that was “disconnected” by the athlete's movement out of the blocks. This disconnection represented an independent event recorded by different tools. A “gap” was measured for some sprint start events between kinetic and kinematic (motion capture) data. Calibration results, measurements of time “gap”, and duration of the independent event were used to validate the accuracy of motion capture and the synchronization system. The results validate the entire experimental set-up and suggest adjustment values for motion capture data. This environment can be used to study other movements and can easily be applied to several sports.

Motion illusion reveals fixation stability of karate athletes

To investigate the effect of smooth pursuit effort against optokinetic nystagmus (OKN) on the magnitude of induced motion, we measured the magnitude of induced motion and eye movements of karate athletes and novices. In Experiment 1, participants were required to pursue a horizontally moving fixation stimulus against a vertically moving inducing stimulus and to point at the most distorted position of the perceived pathway of the fixation stimulus. In Experiments 2 and 3, participants were presented with the inducing stimulus with or without a static fixation stimulus. Experiments 1 and 2 showed a larger magnitude of induced motion and more stable fixation for the athletes than for the novices. Experiment 3 showed no difference in eye movements between the two groups. These results suggest that the magnitude of induced motion reflects fixation stability that may have been strengthened in karate athletes through their experience and training.

Beyond Jackie Robinson: Racial Integration in American College Football and New Directions in Sport History

AbstractThis article seeks to unite a narrative of African American integration in collegiate football with the broader narrative of the Civil Rights Movement. It emphasizes the nebulous history of athletic integration and explores how that process compared to the overall course of civil rights during the twentieth century. Rather than focus on a myriad of schools and regions, it introduces the popular discourse surrounding the largest conflicts over integration in college football. Beyond Jackie Robinson points to four case studies that exemplify how reaction to a game could draw national media attention, transcend sport, and influence the mainstream discourse of race in America. By shifting focus away from the biographies of professional African American sporting figures, Beyond Jackie Robinson contends that collegiate athletic integration was a movement of young student athletes that more closely resembles the broader African American struggle for civil rights in postwar America.

THE EFFECT OF STATIC,BALLISTIC, AND PROPRIOCEPTIVE NEUROMUSCULAR FACILITATION STRETCHING ON VERTICAL JUMP PERFORMANCE

The purpose of this study was to compare the acute effects of different modes of stretching on vertical jump performance. Eighteen male university students (age, 24.3 +/- 3.2 years; height, 181.5 +/- 11.4 cm; body mass, 78.1 +/- 6.4 kg; mean +/- SD) completed 4 different conditions in a randomized order, on different days, interspersed by a minimum of 72 hours of rest. Each session consisted of a standard 5-minute cycle warm-up, accompanied by one of the subsequent conditions: (a) control, (b) 10-minute static stretching, (c) 10-minute ballistic stretching, or (d) 10-minute proprioceptive neuromuscular facilitation (PNF) stretching. The subjects performed 3 trials of static and countermovement jumps prior to stretching and poststretching at 5, 15, 30, 45, and 60 minutes. Vertical jump height decreased after static and PNF stretching (4.0% and 5.1%, p < 0.05) and there was a smaller decrease after ballistic stretching (2.7%, p > 0.05). However, jumping performance had fully recovered 15 minutes after all stretching conditions. In conclusion, vertical jump performance is diminished for 15 minutes if performed after static or PNF stretching, whereas ballistic stretching has little effect on jumping performance. Consequently, PNF or static stretching should not be performed immediately prior to an explosive athletic movement.

Postscript: History as anthropology

Postscript: History as anthropology

Gender, Bilateral Symmetry, and the Knee Extensor Mechanism

Females are substantially more susceptible than males to acute noncontact injury of the anterior cruciate ligament (ACL). Although the cause of disparity in injury rate is not fully understood, numerous extrinsic and intrinsic factors are believed to be associated with ACL injury. We examined knee extensor mechanism function, an extrinsic factor that is critical for the successful execution of athletic movements and activities of daily living. Little is known regarding the influence gender and the unilateral nature of injury on the knee extensor mechanism. PURPOSE: To evaluate and compare the knee extensor mechanism for the right and left legs of males and females during maximal isometric knee extensions. METHODS: Ten healthy college age males and 7 females with no history of lower extremity injury participated. Subjects performed three maximal isometric knee extensions with each leg while lateral radiographs were taken (10, 30, and 50° of knee flexion). Specific anatomical landmarks were digitized from the radiographic images to determine the effective moment arm of the quadriceps force, patellar tendon length, patella height, patellar mechanism and patellar tendon angles, and tibiofemoral and patellofemoral joint spaces. RESULTS: Separate three-way ANOVA (gender x side x angle) with repeated measures on the last two factors revealed several main effects (p<0.05). More specifically, ten of the twelve variables tested varied with knee flexion angle, four variables varied between right and left legs, and 3 varied between males and females. Interestingly, females exhibited decreased patella tendon angles, increased patellofemoral joint space, and increased patella tendon length. CONCLUSION: Our observations may help explain the increased rate of injury in the athletic female population and provide justification for future studies involving the knee extensor mechanism with continued focus on two dimensional radiograph digitizing methods. The absence of a gender difference in the effective moment arm may suggest that the greater knee extension strength in males is due a greater quadriceps strength while a decrease in patella tendon angle will lower the shear component of the patella tendon force and decrease the potential stress on ACL.

Optoelectronic vertical jump height measuring method and device

Various vertical jump height measurement systems are being used today. Mostly used types are mechanical wheel jump-meter, video systems and electrical contact operated systems. In this paper, these systems have been studied and possible errors are defined. It has been determined that the wheel operated systems are setting a limit to the athlete’s movement. There is an error because of moment of inertia. Also, there occurs an error because of the loose wire. Video systems (tabulated list method) have the satisfactory sensitivity, so they can be used to calibrate the device type systems. However, these types of systems have subjective errors since initial position of the athlete affects the measurement results. The cord limits the movement of the athlete in the mechanical wheel operated systems. Moreover, an error occurs in the measurement because of the momentum. Also, another error occurs in stretching of the cord before jumping and the cord is worn out with time. Jump height is to be calculated from rise and fall times in contact operated systems. Fall time is to be extended from the athlete folding his legs. Also this situation causes an error. Mechanical contacts loose their flexibility and electrical properties as the time passes. Even distance between strips causes an error. In addition, movements of athlete’s on the floor between his foot fingers and heel can trigger the contacts and this will be the cause of jump height calculation without jumping. To eliminate these disadvantages a new measuring method for vertical jump height has been developed and a laser operated optoelectronic device designed. In the suggesting method have been measured “the time of flying” same as contact operated method, but fall down on the floor is not to take into account in the new method and athlete cannot affect on the result in this way.

Analyse de la posture et du mouvement et médecine du sport

The use of posture and movement analysis methods has developed during the past 15 years. These methods are of special interest in the field of sport sciences and have allowed to improve the understanding of physiology of posture and movement in athletes. More recently these methods have been used in the field of sport medicine. In some cases, they have helped to identify abnormalities which cannot be seen on standard clinical examination and to understand the mechanism of lesions occurring during sport activities. For the future these methods should provide useful information for understanding the physiopathology of lesions, for developing prevention of pathologies related to sport and for elaborating and assessing new treatment protocols in the field of sport medicine.