SPRING 2020 IN THE SPORTS MEDICINE & MOVEMENT LAB

This Spring the Sports Medicine & Movement Lab has been very busy with on-going research data collections, dissertation data collections, and research presentations. We wanted to briefly highlight the data collections being conducted in the lab as well as the regional ACSM presentations. For more information about the manuscripts being published from the Sports Medicine & Movement Lab, please visit our google scholar page by clicking on this link: Sports Medicine & Movement Lab

ASSOCIATION OF UPPER EXTREMITY PAIN WITH SOFTBALL PITCHING KINEMATICS AND KINETICS

Oliver GD, Friesen K, Barfield J, Giordano K, Anz A, Dugas J, Andrews J. Association of Upper Extremity Pain with Softball Pitching Kinematics and Kinetics. Orthopedic Journal of Sports Medicine. 2019; 7 (8), 2325967119865171. https://journals.sagepub.com/doi/full/10.1177/2325967119865171

Background: There is a paucity of research regarding the relationship between fast-pitch softball pitching mechanics and reported pain. Thus, understanding the pitching mechanics of those pitching with upper extremity pain and those pain free is needed. Purpose: The purpose of this study was to examine lower extremity pitching mechanics, upper extremity kinetics and upper extremity pain in NCAA Division I female softball pitchers. Methods:

Thirty-seven NCAA Division I female softball pitchers (19.71±1.29 yrs.; 173.05±8.17 cm; 78.31±12.07 kg) from across the United States were recruited to participate. Participants were divided into two groups: upper extremity pain (19.7±1.2 yrs; 172.6±11.5 cm; 86.7±13.0 kg; n=13), and pain free (19.9±1.3 yrs; 174.3±5.0 cm; 74.8±10.0 kg; n=24). An electromagnetic tracking system was used to obtain kinematic and kinetic data during the rise ball softball pitch. Results: At foot contact (F3,33 =7.01, p=.001), the backward elimination regression revealed that stride length, trunk rotation, and center of mass (COM) significantly explained about 29% of variance with softball pitchers currently experiencing upper extremity pain (Adj. R2=.29). Conclusion: The kinematic variables of increased trunk rotation towards the pitching arm side, increased stride length, and a posteriorly shifted COM are associated with upper extremity pain in collegiate softball pitchers. Variables early in the pitching motion that do not set a working and constructive proximal kinetic chain foundation, for the rest of the pitch to follow, could be associated with breakdowns more distal in the kinetic chain possibly increasing upper extremity pain susceptibility. Clinical Relevance: The identification of pitching mechanics associated with pain allows clinicians to develop exercises to avoid such mechanics known to be associated with pain. Avoiding mechanics associated with pain may help reduce the prevalence of pain in softball windmill pitchers, as well as help coaches incorporate quantitative biomechanics into their instruction.

EPIDEMIOLOGY OF SHOULDER AND ELBOW INJURIES AMONG US HIGH SCHOOL SOFTBALL PLAYER

Oliver GD, Saper M, Drogosz M, Plummer H, Arakkal A, Comstock D, Anz A, Andrews J, Fleisig G. Epidemiology of Shoulder and Elbow Injuries Among US High School Softball Players, 2005-2006 Through 2016-2017. Orthopedic Journal of Sports Medicine. 2019; 7 (9), 2325967119867428. https://journals.sagepub.com/doi/full/10.1177/2325967119867428

Background: Injury prevalence has been well-described among baseball athletes, similarly, a better understanding of injuries in softball athletes is needed. Purpose: To examine shoulder and elbow injury epidemiology among high school softball athletes in the United States (US). Methods: Injury data were obtained from the National High School Sports-Related Injury Surveillance Study, which captures data from a large national sample of US high schools. Annually, a random sample of 100 high schools provided a representative sample with respect to the 4 US Census geographic regions and two school sizes (cut point 1,000 students). Athletic trainers from participating schools reported data for athletic exposures (AEs) (practice or competition) and shoulder and elbow injuries from 2005-2006 through 2016-2017. Results: A total of 239 shoulder injuries and 85 elbow injuries occurred within 2,095,329 AEs. The overall shoulder injury rate was 1.14 per 10,000 AEs whereas the overall elbow injury rate was 0.41 per 10,000 AEs. Injuries to the shoulder were more likely to occur during competition compared to practice (rate ratio: 1.28; 95%CI 0.99-1.65) . Half of the shoulder (50.4%) and elbow (50.0%) injuries were due to an overuse/chronic mechanism. Of the athletes sustaining an injury, 86.8% with shoulder injuries and 93.0% with elbow injuries returned to play within 21 days. Only 16.7% of shoulder injuries and 17.5% of elbow injuries were sustained by pitchers. Conclusion: Shoulder and elbow injury rates, time to return, and percent of injuries among pitchers are far lower in high school softball than previously reported values for high school baseball. Clinical Relevance: Compared to baseball, there are relatively low incidences of shoulder and elbow injuries in high school softball, with few injuries requiring lengthy time to return to play.

GLENOHUMERAL AND HIP RANGE OF MOTION IN YOUTH SOFTBALL ATHLETES

As participation and injuries are on the rise in softball, it is important to assess potential areas of injury susceptibility within the kinetic chain. Understanding range of motion (ROM) patterns at the youth level in both pitchers and position players could assist in injury prevention and development of position-specific conditioning programs. Therefore, the purpose of this study was to compare measures of bilateral shoulder and hip ROM between youth softball pitchers and positional players. Fifty-two youth softball athletes (12.7 ± 2.1 yrs.; 160.28 ± 10.98 cm; 59.31 ± 15.07 kg) participated. Bilateral hip and shoulder ROM were measured among position players (n = 23) and pitchers (n = 29). A 2 (position/player) x 2 (dominant/non-dominant) x 2 (IR/ER) ANOVA was performed for both the shoulder and the hip to examine the differences in ROM between position players and pitchers. Data revealed that pitchers have less non-throwing shoulder ER ROM (100.12 ± 11.21) than positional players (106.92 ± 9.14). Additionally, both position players and pitchers have significantly more hip (p < .001) and shoulder (p < .001) external ROM than internal ROM, with no significant differences between throwing and non-throwing sides. It is important that coaches and clinicians are aware of these adaptions between overhand and underhand throwing, in order to properly develop conditioning and rehabilitation programs to alleviate injury susceptibility and cater to position-specific demand. Additionally, the current data suggest many of the functional adaptations seen within older populations are not fully birthed until after youth.

Friesen KB, Downs JL, Wasserberger KW, Shannon D, Oliver GD. (2019). Glenohumeral and Hip Range of Motion in Youth Softball Athletes. [published online ahead of print, November 21, 2019]. International Journal of Sports Medicine, 40, 1-6. doi: 10.1055/a-1019-7742

ASSOCIATION OF UPPER-BODY KINEMATICS AND EARNED RUN AVERAGE OF NATIONAL COLLEGIATE ATHLETIC ASSOCIATION DIVISION I SOFTBALL PITCHERS

Friesen KB, Barfield JW, Murrah WM, Dugas JR, Andrews JR, Oliver GD. (2019). The Association of Upper-Body Kinematics and Earned Run Average of National Collegiate Athletic Association Division I Softball Pitchers. [published online ahead of print, July 22, 2019]. Journal of Strength and Conditioning Research. doi: 10.1519/jsc.0000000000003287

Although recent literature has increased examination of the association of injury and biomechanics, there remains a lack of evidence supporting optimal windmill pitch mechanics. Therefore, the purpose of this study was to investigate trunk and pitching arm kinematics and their association with performance outcome: earned run average (ERA), in collegiate softball pitchers. Twenty-three NCAA Division I collegiate softball pitchers (20.14 ± 1.07 years; 173.93 ± 6.68 cm; 85.79 ± 11.06 kg) performed three maximal effort rise ball pitches to a catcher located at a distance of 43 ft. (13.11 m). Kinematic data of the trunk and pitching arm were collected using an electromagnetic tracking system. A multiple regression analysis was performed at each pitch event: top of backswing, foot contact, ball release, and follow through. The multiple regression at foot contact showed an overall statistically significant regression equation, (F6, 16 = 3.7, p = .017) and explained approximately 42% of the variance in ERA (R = .579, Adj. R2 = .421). Results revealed that those pitchers who had greater trunk (SE = .018, t = -2.5, p = .023) and elbow flexion (SE = .006, t = -4.2, p = .001) at the event of foot contact had lower ERAs. The present study supported previous research on the importance of trunk and elbow angle at front foot contact on rise ball pitch performance. These key technique points and the importance of elbow flexors should be explored in future research and potentially visually attended to by coaches and strength professionals.

EFFECTS OF A SIMULATED GAME ON PITCHING KINEMATICS IN YOUTH SOFTBALL PITCHERS

Downs J, Friesen K, Anz A, Dugas J, Andrews J, Oliver G. Effects of a Simulated Game on Pitching Kinematics in Youth Softball Pitchers. International Journal of Sports Medicine. 2020; https://www.thieme-connect.com/products/ejournals/html/10.1055/a-1062-6475

Despite evidence that overuse is the most common mechanism of injury, softball pitchers currently have no pitch count regulations. Pain has been associated with certain pitching pathomechanics, and some reports indicate increased pain following a single pitching bout. Therefore, the purpose of this study was to examine trunk, and lower extremity kinematics during the first and last inning of a game, as well as last inning pitch volume in youth softball pitchers. Thirty-two youth softball pitchers (12.4±1.6 years, 159.4±8.9 cm, 62.0±13.6 kg) pitched a simulated game. Three fastballs were averaged and analyzed from the first and last inning. Kinematic data were collected at 100Hz using an electromagnetic system, synced with motion analysis software. A Wilcoxon signed rank test revealed pitchers exhibited less trunk rotation toward their pitching arm side in the last inning. A bivariate Pearson’s correlation showed volume of pitches was correlated with stride length (r=.367, p=.039) and center of mass (r=.364, p=.041) at the start of the pitch, and trunk flexion at top of pitch (r=-.392, p=.026), foot contact (r=-.413, p=.019), and follow-through (r=-.436, p=.013). This study found that pitching a simulated game did result in altered pitching mechanics, meanwhile pitch volume was also correlated with pitching mechanics.

GLENOHUMERAL EXTERNAL ROTATION WEAKNESS PARTIALLY ACCOUNTS FOR INCREASED HUMERAL ROTATION TORQUE IN YOUTH BASEBALL PITCHERS

Objectives: To examine differences in shoulder internal rotation (IR) torque among youth pitchers of above and below average relative glenohumeral (GH) rotation strength levels. It was hypothesized that differences in IR torque during the pitching motion would could be explained by differences in relative IR and external rotation (ER) strength. Methods: Isometric GH rotation strength and upper extremity pitching mechanics were assessed in 78 male youth baseball pitchers (12.7 ± 2.0 yrs; 1.63 ± 14.0 m; 56.9 ± 12.4 kg). Shoulder IR torque during the pitch was examined at maximum humeral external rotation (MER) and throughout the arm acceleration phase (ACC). Multivariate analysis of covariance (MANCOVA) was used to examine the differences in pitching IR torque between GH strength groups. Results: A significant main effect of ER strength on the dependent variables was present after controlling for fastball velocity (λ = 0.855, F2,72 = 6.13, p = 0.003, = 0.145). Follow up univariate tests indicated significant differences in IR torque between strength groups at MER (F1,73 = 12.36, p < 0.001, = 0.145) and during ACC (F1,73 = 6.65, p = 0.012, = 0.083). Participants who displayed ER strength at or below the group mean experienced greater IR torque at MER and greater average IR torque during ACC than participants who displayed ER strength above the group mean. Conclusions: Weakness of the GH ER musculature partially accounts for increased shoulder IR torque during pitching.

Wasserberger KW, Barfield JW, Downs JL, Oliver GD. Glenohumeral External Rotation Weakness Partially Accounts for Increased Humeral Rotation Torque in Youth Baseball Pitchers. Journal of Science and Medicine in Sport.

USING THE SINGLE LEG SQUAT AS AN ASSESSMENT OF STRIDE LEG KNEE MECHANICS IN ADOLESCENT BASEBALL PITCHERS

Objectives: Lack of control of the lower extremity or trunk during single leg tasks is often associated with pathomechanic adaptations during the pitching motion which may increase the risk of pain and injury to the upper extremity. The objectives of the study were to determine the amount of variability in stride knee mechanics accounted for by compensations during a common movement assessment, the single leg squat (SLS) and to establish the usefulness of SLS as a screening tool for at-risk athletes. Methods:

Sixty-one adolescent baseball pitchers performed a SLS on each leg. Participants performed three fastball pitches to a catcher at a regulation distance. Kinematic data were collected at 100 Hz using an electromagnetic tracking device. Results: MANOVAs with follow-up one-way ANOVAs were used to examine the amount of variance in pitching knee mechanics explained by SLS compensations. At stride foot contact, there was a significant effect of SLS valgus angle on knee valgus angle (F1,51 = 23.16, p < 0.001, ) and valgus moment (F1,51 = 8.28, p = 0.006, ). At ball release (BR), there was a significant effect of SLS valgus angle on flexion angle (F1,51 = 9.37, p = 0.004, ) and valgus angle (F1,51 = 26.93, p < 0.001, ). Examination of the average values occurring between SFC and BR, revealed a significant effect of SLS valgus angle on knee valgus angle (F1,51 = 30.91, p < 0.001, ). Conclusions: SLS compensations are potentially a useful screening tool for stride knee mechanics in adolescent baseball pitchers.

Wasserberger KW, Barfield JW, Anz A, Andrews J, Oliver GD. Using the Single Leg Squat as an Assessment of Stride Leg Knee Mechanics in Adolescent Baseball Pitchers. Journal of Science and Medicine in Sport. 2019; 22(11): 1254-1259. https://www.sciencedirect.com/science/article/abs/pii/S1440244019300337

THE EFFECT OF LOAD MAGNITUDE ON MUSCLE ACTIVATION DURING UNILATERAL FRONT RACKED DUMBBELL CARRIES

Background: Weighted carries may increase strength and stability of the scapular and lumbo-pelvic hip complex (LPHC) musculature; however, load magnitude should be considered since variations may affect muscle activation. The purpose of this study was to quantify the effect of load magnitude on muscle activation during unilateral front racked dumbbell carries. Methods: Eight (22.8 ± 2.9yrs, 178.0 ± 4.8cm, 72.8 ± 29.6kg) healthy and resistance trained individuals completed 3 trials of 3 load conditions across a 12 m distance with a dumbbell held in a front racked position on the participant’s dominant side. Loading conditions were 25% (light), 30% (moderate), and 35% (heavy) of body weight. Electromyography data were measured on the dominant (1) upper (UT) and (2) lower trapezius (LT), (3) latissimus dorsi (LD), (4) serratus anterior (SA), non-dominant (5) gluteus medius (GM), and bilateral (6-7) external obliques. Maximum voluntary isometric contraction (MVIC) testing established baseline muscle activity to which subsequent trials were normalized. A 3 (load) x 7 (muscle) repeated measures analysis of variance (RM∙ANOVA) compared muscle activation (% MVIC) between load conditions. Results: The RM∙ANOVA revealed a significant load by muscle interaction [F(2.540, 17.783) = 4.154, p = 0.026]. Post hoc analysis revealed a significant difference between light and heavy loads in UT (p = 0.005), LT (p = 0.006), LD (p = 0.007), SA (p = 0.015), and non-dominant external oblique (p = 0.030), where heavy loads had greater activation. There was also a significant difference between light and moderate loads in the UT (p = 0.017) and non-dominant external oblique (p = 0.024), where moderate loads had greater activation. Conclusion: Increased load magnitude resulted in greater scapular and LPHC activation during unilateral front racked dumbbell carries. Future research should analyze the effect of load magnitude during weighted carries with other load placement variations.

ACUTE AND CHRONIC KINEMATIC EFFECTS OF A RESISTANCE TUBING TRAINING DEVICE ON YOUTH BASEBALL AND SOFTBALL SWINGS

Objective: Baseball and softball athletes often use swing training implements in preparation for an at bat, or to develop strength/power. The purpose of the present study is to examine the kinematic effects of a resistance tubing training device on youth baseball and softball swings both acutely, and after a 4-week intervention. Methods: Twenty youth baseball and softball athletes participated. Ten completed the 4-week intervention and returned for follow up testing. Kinematic data were collected using an electromagnetic motion capture system on baseline swings. Participants then swung with the resistance tubing device, then took it off, and subsequent swings were recorded. Participants completed a 4-week intervention using the swing trainer, then reported back for follow-up testing. All collected swings were taken off a tee with the instructions to hit line drives up the middle of the cage. Data were analyzed for center of mass (COM) positioning over base of support (BOS), hand velocity, and hand path. Results: Repeated measures analysis of variance revealed no significant changes in COM over BOS, hand velocity, or hand path between time points: baseline, acute, and follow-up. Conclusion: The absence of significant kinematic changes means the resistance tubing swing training device could be used as a preparation tool for at-bats without the negative performance indicators reported in previous research on weighted implements.

Giordano K, Wasserberger K, Barfield J, Oliver GD. Acute and Chronic Kinematic Effect of a Resistance Tubing Training Device on Youth Baseball and Softball Swings. Journal of Athletic Enhancement. 2019: 8:(2) 1-7. https://www.scitechnol.com/peer-review/acute-and-chronic-kinematic-effect-of-a-resistance-tubing-training-device-on-youth-baseball-and-softball-swings-ARX8.php?article_id=9674

THE EFFECT OF LOAD MAGNITUDE ON MUSCLE ACTIVATION DURING UNILATERAL DUMBELL CARRIES

Weighted carries may increase strength and stability of the scapular and lumbo-pelvic hip complex (LPHC) musculature; however, load magnitude should be considered since variations may affect muscle activation. The purpose of this study was to quantify the effect of load magnitude on muscle activation during unilateral front racked dumbbell carries. Eighteen healthy and resistance trained individuals completed 3 trials of 3 load conditions (light, moderate, and heavy) across a 12 m distance with a dumbbell held in an overhead, front racked, and suitcase position on their dominant side. Prescribed loads were relative to position and body weight. Electromyography data were measured on the dominant (1) upper (UT) and (2) lower trapezius (LT), (3) latissimus dorsi (LD), (4) serratus anterior (SA), and (5-6) bilateral gluteus medius (GM) and (7-8) external obliques. Maximum voluntary isometric contraction (MVIC) testing established baseline muscle activity to which subsequent trials were normalized. A 3 (load) x 8 (muscle) repeated measures analysis of variance (RM∙ANOVA) compared muscle activation (% MVIC) between load conditions. Analysis revealed increased load magnitude resulted in greater scapular and LPHC activation during unilateral dumbbell carries.

Bordelon NM, Wasserberger KW, Cassidy MM, Oliver GD. The Effects of Load Magnitude and Placement on Muscle Activity during Unilateral Weighted Dumbbell Carries. Journal of Strength and Conditioning Research.

3MT People's Choice Award

Doctoral student Kenzie Friesen won the People’s Choice Award for the 3MT at Auburn University. The 3MT, or Three Minute Thesis, is an annual competition hosted by Auburn's Graduate School. It is a research communication competition developed by The University of Queensland. The exercise challenges graduate students to present a compelling oration on their thesis or dissertation topic and its significance in just three minutes. 3MT develops academic, presentation, and research communication skills and supports the development of research students’ capacity to effectively explain their research in language appropriate to a non-specialist audience.

National Strength and Conditioning Association Foundation Scholarships

Nicole Bordelon and Kevin Giordano receive scholarships from National Strength and Conditioning Association Foundation

The National Strength and Conditioning Association Foundation recently awarded scholarships to Nicole Bordelon and Kevin Giordano. Nicole received the foundation’s minority scholarship while Kevin received the challenge scholarship.

Nicole said, “I am very thankful to be a National Strength and Conditioning Association minority scholarship recipient. This scholarship will fully cover registration and travel expenses to present research at national and regional level conferences this year. Having the capability to present at multiple conferences broadens networking opportunities, increases research exposure to target populations, and provides multiple opportunities to fine tune my presentation skills.”

Kevin said, “I will use this money mostly for travel to conferences and to cover submission fees for abstracts to present at conferences. This will allow me t to travel more and present at higher conferences. This scholarship is meaningful to me because I won it in 2016 which allowed me to afford to go to Combined Sections Meeting, where I made a connection that led me to Auburn for my PhD.”