Position-Specific Physical Workload Intensities in American Collegiate Football Training

Quantifying player training loads allows football coaching staff to make informed adjustments to the volume and intensity of training. Physical workload intensity in American football practices have not been extensively quantified. The current study examined physical workload intensities across positions in American collegiate football during training. Data from player tracking technology (Catapult Vector) were collected from 72 American football players (National Collegiate Athletic Association Division I) during in-season practices. Players were involved in individualized skill (indy), team playbook (team), and special team (ST) drills during practice and analyzed for their specialist offensive or defensive role (e.g., linebacker or wide receiver). Player running (i.e., high-speed running and sprint) and accelerations (i.e., highintensity PlayerLoad and high-intensity inertial movement analysis) per minute were of interest. Drill type and practice day had significant effects on all workload intensity metrics (p < 0.01), but not position. Greater running intensities were seen in ST drills compared with other drill types. Tuesday practice sessions had greater overall intensities compared with other days. Interaction effect of position and drill type was significant (p <0.001) for all intensity metrics, indicating that position groups exhibited unique workload responses to the drill types. Drill type and practice day interaction effect was significant for all intensity metrics (p <0.01). The findings may be informative for coaches to tailor physical workloads of practice drills for positional roles in preparation for games and practices. Player tracking technology can add value for strength and conditioning coaches to adjust training programs based on position-specific on-field demands of players

Traumatic quadriceps rupture in a patient with patellectomy: a case report

<p>Abstract</p> <p>Introduction</p> <p>Acute traumatic, unilateral, quadriceps rupture after patellectomy is rare.</p> <p>Case presentation</p> <p>We present a 42-year old male who experienced a unilateral left quadriceps tendon rupture following assault by four people. Twenty-seven years before this injury, the patient had suffered ipsilateral femur and comminuted patellar fractures, which were managed by intramedullary nailing and patellectomy respectively. We performed primary end to end repair of the torn tendon. Postoperatively, histology revealed findings consistent with pre-existent degenerative changes. The patient made good recovery, and returned to his former occupation which was reliant on his ability to drive.</p> <p>Conclusion</p> <p>Degenerative changes of the tendon of the extensor mechanism of knee following patellectomy may predispose the quadriceps tendon to traumatic rupture. Early operative intervention and protracted rehabilitation are required to obtain the best functional results.</p

Impact of leg lengthening on viscoelastic properties of the deep fascia

<p>Abstract</p> <p>Background</p> <p>Despite the morphological alterations of the deep fascia subjected to leg lengthening have been investigated in cellular and extracellular aspects, the impact of leg lengthening on viscoelastic properties of the deep fascia remains largely unknown. This study aimed to address the changes of viscoelastic properties of the deep fascia during leg lengthening using uniaxial tensile test.</p> <p>Methods</p> <p>Animal model of leg lengthening was established in New Zealand white rabbits. Distraction was initiated at a rate of 1 mm/day and 2 mm/day in two steps, and preceded until increases of 10% and 20% in the initial length of tibia had been achieved. The deep fascia specimens of 30 mm × 10 mm were clamped with the Instron 1122 tensile tester at room temperature with a constant tensile rate of 5 mm/min. After 5 load-download tensile tests had been performed, the specimens were elongated until rupture. The load-displacement curves were automatically generated.</p> <p>Results</p> <p>The normal deep fascia showed typical viscoelastic rule of collagenous tissues. Each experimental group of the deep fascia after leg lengthening kept the properties. The curves of the deep fascia at a rate of 1 mm/day with 20% increase in tibia length were the closest to those of normal deep fascia. The ultimate tension strength and the strain at rupture on average of normal deep fascia were 2.69 N (8.97 mN/mm²) and 14.11%, respectively. The increases in ultimate tension strength and strain at rupture of the deep fascia after leg lengthening were statistically significant.</p> <p>Conclusion</p> <p>The deep fascia subjected to leg lengthening exhibits viscoelastic properties as collagenous tissues without lengthening other than increased strain and strength. Notwithstanding different lengthening schemes result in varied viscoelastic properties changes, the most comparable viscoelastic properties to be demonstrated are under the scheme of a distraction rate of 1 mm/day and 20% increase in tibia length.</p

Changes in a Starting Pitcher’s Performance Characteristics Across the Duration of a Major League Baseball Game

Purpose:With a view to informing in-game decision making as it relates to strategy and pitcher health, this study examined changes in pitching-performance characteristics across 9 innings of Major League Baseball (MLB) games.Methods:129 starting MLB pitchers met the inclusion criteria for this study. Pitch type, speed, ball movement, release location, and strike-zone data—collected using the MLB’s ball-tracking system, PITCHf/x—were obtained for 1,514,304 pitches thrown from 2008 to 2014.Results:Compared with the 1st inning, the proportion of hard pitches thrown decreased significantly until the 7th inning, while the proportions of breaking and off-speed pitches increased. Significant decreases in pitch speed, increases in vertical movement, and decreases in release height emerged no later than the 5th inning, and the largest differences in all variables were generally recorded between the 1st inning and the late innings (7–9). Pitchers were most effective during the 2nd inning and significantly worse in innings 4 and 6.Conclusion:These data revealed that several aspects of a starting pitcher’s pitching characteristics exhibited changes from baseline as early as the 2nd or 3rd inning of an MLB game, but this pattern did not reflect the changes in his effectiveness. Therefore, these alterations do not appear to provide reasonable justification for relieving a starting pitcher, although future work must address their relevance to injury. From an offensive standpoint, batters in the MLB should anticipate significantly more hard pitches during the early innings but more breaking and off-speed pitches, with decreasing speed, as the game progresses.</jats:sec

Predictors of Ulnar Collateral Ligament Reconstruction in Major League Baseball Pitchers

Background: Ulnar collateral ligament (UCL) reconstruction surgeries in Major League Baseball (MLB) have increased significantly in recent decades. Although several risk factors have been proposed, a scientific consensus is yet to be reached, providing challenges to those tasked with preventing UCL injuries. Purpose: To identify significant predictors of UCL reconstruction in MLB pitchers. Study Design: Case control study; Level of evidence, 3. Methods: Demographic and pitching performance data were sourced from public databases for 104 MLB pitchers who underwent UCL reconstruction surgery and 104 age- and position-matched controls. These variables were compared between groups and inserted into a binary logistic regression to identify significant predictors of UCL reconstruction. Two machine learning models (naïve Bayes and support vector machine) were also employed to predict UCL reconstruction in this cohort. Results: The binary linear regression model was statistically significant (χ2(12) = 33.592; P = .001), explained 19.9% of the variance in UCL reconstruction surgery, and correctly classified 66.8% of cases. According to this model, (1) fewer days between consecutive games, (2) a smaller repertoire of pitches, (3) a less pronounced horizontal release location, (4) a smaller stature, (5) greater mean pitch speed, and (6) greater mean pitch counts per game were all significant predictors of UCL reconstruction. More specifically, an increase in mean days between consecutive games (odds ratio [OR], 0.685; 95% CI, 0.542-0.865) or number of unique pitch types thrown (OR, 0.672; 95% CI, 0.492-0.917) was associated with a significantly smaller likelihood of UCL reconstruction. In contrast, an increase in mean pitch speed (OR, 1.381; 95% CI, 1.103-1.729) or mean pitches per game (OR, 1.020; 95% CI, 1.007-1.033) was associated with significantly higher odds of UCL reconstruction surgery. The naïve Bayes classifier predicted UCL reconstruction with an accuracy of 72% and the support vector machine classifier with an accuracy of 75%. Conclusion: This study identified 6 key performance factors that may present significant risk factors for UCL reconstruction in MLB pitchers. These findings could help to enhance the prevention of UCL reconstruction surgery in MLB pitchers and shape the direction of future research in this domain. </jats:sec

Biomechanical Loads and Their Effects on Player Performance in NCAA D-I Male Basketball Games

Basketball games and training sessions are characterized by quick actions and many scoring attempts, which pose biomechanical loads on the bodies of the players. Inertial Measurement Units (IMUs) capture these biomechanical loads as PlayerLoad and Inertial Movement Analysis (IMA) and teams collect those data to monitor adaptations to training schedules. However, the association of biomechanical loads with game performance is a relatively unexplored area. The aims of the current study were to determine the statistical relations between biomechanical loads in games and training with game performance. Biomechanical training and game load measures and player-level and team-level game stats from one college basketball team of two seasons were included in the dataset. The training loads were obtained on the days before gameday. A three-step analysis pipeline modeled: (i) relations between team-level game stats and the win/loss probabilities of the team, (ii) associations between the player-level training and game loads and their game stats, and (iii) associations between player-level training loads and game loads. The results showed that offensive and defensive game stats increased the odds of winning, but several stats were subject to positional and individual performance variability. Further analyses, therefore, included total points [PTS], two-point field goals, and defensive rebounds (DEF REB) that were less subject to those influences. Increases in game loads were significantly associated with game stats. In addition, training loads significantly affected the game loads in the following game. In particular, increased loads 2 days before the game resulted in increased expected game loads. Those findings suggested that biomechanical loads were good predictors for game performance. Specifically, the game loads were good predictors for game stats, and training loads 2 days before gameday were good predictors for the expected game load. The current analyses accounted for the variation in loads of players and stats that enabled modeling the expected game performance for each individual. Coaches, trainers, and sports scientists can use these findings to further optimize training plans and possibly make in-game decisions for individual player performance