Tennis player Andy Murray’s solution to hip pain is a source of hope for patients around the world and his recovery challenges the limits of current medicine. I just saw his appearance at the Indian Wells ATP in the US (October 2021), and I was amazed to see him play so well! Andy Murray’s disease is called femuracetabular impingement and is a syndrome characterized by injury to the hip joint, which is the part of the pelvis where the femur fits. This disease is what affected our greatest Brazilian tennis player Gustavo “Guga” Cuerton in the past and we see today that when the surface enters an advanced process of degeneration, it can develop into joint wear , and depending on the case, its replacement by a prosthesis.
Reactive strength index (RSI) is used frequently in the testing and monitoring of athletes. Associations with sports performance measures may vary dependent on the task but a literature synthesis has not been performed. Objectives
The aim of this meta-analysis was to examine associations between RSI measured during rebound jumping tasks and measures of strength, linear and change of direction speed, and endurance performance. Methods
A systematic literature search with meta-analysis was conducted using databases PubMed, SPORTDiscus, Web of Science, and Ovid. Inclusion criteria required studies to (1) examine the relationship between RSI and an independent measure of physical or sporting performance for at least one variable; and (2) provide rebound test instructions to minimise ground contact time and maximise displacement of the jump. Methodological quality was assessed using a modified version of the Downs and Black Quality Index tool. Heterogeneity was examined via the Q statistic and I2. Pooled effect sizes were calculated using a random-effects model, with Egger’s regression test used to assess small study bias (inclusive of publication bias). Results
Of the 1320 citations reviewed, a total of 32 studies were included in this meta-analysis. RSI was significantly and moderately associated with strength (isometric: r = 0.356 [95% CI 0.209–0.504]; isotonic: r = 0.365 [0.075–0.654]; pooled strength measures: r = 0.339 [0.209–0.469]) and endurance performance (r = 0.401 [0.173–0.629]). Significant moderate and negative associations were indicated for acceleration (r = − 0.426 [− 0.562 to − 0.290]), top speed (r = − 0.326 [− 0.502 to − 0.151]), and significant large negative associations were noted for change of direction speed (r = − 0.565 [− 0.726 to − 0.404]). Heterogeneity was trivial to moderate across all measures (I2 = 0–66%), and significant for isotonic strength and change of direction speed (p < 0.1). Evidence of small study bias was apparent for both acceleration and change of direction speed (p < 0.05).
We identified primarily moderate associations between RSI and independent measures of physical and sporting performance, and the strength of these relationships varied based on the task and physical quality assessed. The findings from this meta-analysis can help practitioners to develop more targeted testing and monitoring processes. Future research may wish to examine if associations are stronger in tasks that display greater specificity.
Frontiers in Sports and Active Living journal from
Background: The purpose of this study was to examine seasonal changes in training load (TL), neuromuscular performance, subjective recovery, and stress state, and to investigate the relationships between acute and chronic TL and neuromuscular performance in competitive female soccer players.
Methods: Nine competitive female soccer players (20.0 ± 1.7 years; 60.3 ± 6.3 kg; 164.0 ± 5.8 cm) completed the Short Recovery and Stress Scale and the countermovement jump (CMJ) with polyvinyl chloride pipe (CMJ0) and 20 kg barbell (CMJ20) at 2–3 h before 1st match (NC1), 6th match (NC2), 9th match (C1), and 15th match (C2) of the competitive season. TL included total distance, high-speed running, and PlayerLoad. Acute and chronic TL was calculated by using the average of 2 days (D2), 7 days (D7), and 21 days (D21) prior to four different match play.
Results: Significant decreases were found from NC1 to C1 in D7 total distance [p = 0.03, Cohen’s effect size (dz) = 1.40]. D7 total distance and PlayerLoad significantly decreased from NC to C1 and C2 (p = 0.001–0.01, dz = 1.40–1.72). Significant increases were observed from NC1 to C1 in CMJ0 jump height (p = 0.03, dz = 1.40), (p = 0.021, dz = 1.44), and peak power (p = 0.03, dz = 1.32). Significant negative correlations were observed for D7 total distance and CMJ0 jump height (p = 0.02, r = 0.79) and peak power (p = 0.03, r = 0.71) at C2, while significant positive correlations were observed at C1 for D7 PlayerLoad and CMJ0 jump height (p = 0.02, r = 0.80).
Conclusion: Polyvinyl chloride pipe (CMJ0) jump height and peak power may increase from preseason to the midcompetitive season. Seasonal variations may affect the relationships between D7 TL and CMJ0 performance. [full text]
The best possible finishing time for a runner competing in distance track events can be estimated from their critical speed (CS) and the finite amount of energy that can be expended above CS (D’). During tactical races with variable pacing, the runner with the ‘best’ combination of CS and D’ and, therefore, the fastest estimated finishing time prior to the race, does not always win. We hypothesized that final race finishing positions depend on the relationships between the pacing strategy employed, the athletes’ initial CS, and their instantaneous D’ (i.e., D’ balance) as the race unfolds. Using publicly available data from the 2017 IAAF World Championships men’s 5,000 m and 10,000 m races, race speed, CS, and D’ balance were calculated. The correlation between D’ balance and actual finishing positions was non-significant utilizing start-line values but improved to R2 > 0.90 as both races progressed. The D’ balance with 400 m remaining was strongly associated with both final 400 m split time and proximity to the winner. Athletes who exhausted their D’ were unable to hold pace with the leaders, whereas a high D´ remaining enabled a fast final 400 m and a high finishing position. The D’ balance model was able to accurately predict finishing positions in both a ‘slow’ 5,000 m and a ‘fast’ 10,000 m race. These results indicate that while CS and D’ can characterize an athlete’s performance capabilities prior to the start, the pacing strategy that optimizes D’ utilization significantly impacts final race outcome. [full text]
Muscle design constraints preclude simultaneous specialization of the vertebrate locomotor system for explosive and economical force generation. The resulting performance trade-off between power and economy has been attributed primarily to individual differences in muscle fiber type composition. While certainly crucial for performance specialization, fiber type likely interacts with muscle architectural parameters, such as fascicle length, to produce this trade-off. Longer fascicles composed of more serial sarcomeres can achieve faster shortening velocities, allowing for greater power production. Long fascicles likely reduce economy, however, because more energy-consuming contractile units are activated for a given force production. We hypothesized that longer fascicles are associated with both increased power production and locomotor cost. In a set of 11 power- and 13 endurance-trained recreational athletes, we measured 1) muscle fascicle length via ultrasound in gastrocnemius lateralis, gastrocnemius medialis, and vastus lateralis, 2) maximal power during cycling and countermovement jumps, and 3) running cost of transport. We estimated muscle fiber type noninvasively based on the pedaling rate at which maximal cycling power occurred. As predicted, longer gastrocnemius muscle fascicles were correlated with greater lower-body power production and cost of transport. Multiple regression analyses revealed that variability in maximal power was explained by fiber type (48% for cycling; 25% for jumping) and average fascicle length (18% for cycling; 12% for jumping), while average fascicle length accounted for 15% of the variation in cost of transport. These results suggest that, at least for certain muscles, fascicle length plays an important role in the power versus economy performance trade-off.
A couple of months back, Andrew Cresci was watching a broadcast of a San Francisco Giants game when something caught his attention. The announcers from the opposing team brought up the unusual way the Giants were conducting batting practice at Oracle Park. Instead of a gray-haired coach lobbing balls at 40 mph or so at hitters, Giants batters were facing two pitches machines: one throwing at game-level velocity, the other spitting out darting breaking balls. The Giants were trying to make practice more game-like.
This is exactly what they were trying to accomplish with hitter training at Driveline Baseball, a private training facility where Cresci is a hitting instructor. At Driveline, coaches try to make the practice environment more challenging. After all, Cresci says, that’s what happens in every other major sport in preparing for a game. For instance, in football, teams practice nearer game speeds and have scout teams simulate opponents. MLB? Not so much.
“For all its metrics, all of its scouting reports and the advanced data MLB has, you hear a lot of things about how the preparation hasn’t really changed at all the last few years,” Cresci told theScore. “Their preparation is the least game-like.”
The avoidance and mitigation of energy wastage have attracted increasing attention in the context of global warming and climate change. With advances in materials science, diverse multifunctional materials with high thermal conductivity have shown excellent energy-saving potential. In this study, a hybrid film exhibiting high thermal conductivity with excellent stretchability and washability was prepared. First, a simple surface modification of boron nitride (BN) was performed to realize a modified boron nitride (BNOH) filler. Next, an organic dispersant was synthesized to enhance the dispersion of BNOH and graphene nanoplatelets (GNPs) in the proposed composite. Subsequently, a simple procedure was used to combine the dispersed GNPs and BNOH fillers with thermoplastic polyurethane (TPU) to fabricate a hybrid structure. The hybrid films composed of BNOH–GNP/TPU with a dispersant exhibited a high thermal conductivity of 12.62 W m–1 K–1 at a low filler loading of 20 wt.%. This hybrid film afforded excellent stretchability and washability, as indicated by the very small thermal-conductivity reduction to only 12.23 W m–1 K–1 after 100 cycles of fatigue testing and to 12.01 W m–1 K–1 after 10 washing cycles. Furthermore, the cooling and hydrophobicity properties of the hybrid film were enhanced when compared with neat TPU. Overall, our approach demonstrates a simple and novel strategy to break the passive effect of traditional commercial cooling clothing by combining a high-thermal-conductivity film with an active cooling source to amplify the cooling effect and develop wearable cooled smart clothes with great commercial potential.
WKRC (Dayton, OH), Bob Herzog & Stephanie Kuzydym from
Every year, the Korey Stringer Institute works to prevent sudden death in athletes by reviewing state high school health and safety policies. It found Ohio hasn’t made any changes to its sport safety policies for high school athletes in a year.
Stu Wilson’s life is one of hundreds of athletic trainers Local 12 has spoken to in the last two years, and, like most athletic trainers, if you ask a question about the profession, he’ll tell you all about why he loves to oversee the health and safety of the sidelines.
The NFL can still do more to prevent concussions without taking away what makes the sport exciting, according to its medical director.
League representatives met with their Premier League counterparts on Wednesday to share thoughts on concussion and other areas of player health.
The NFL’s protocols are often considered among the strictest in the world, and since 2002 it has made more than 50 rule changes designed to eliminate potentially dangerous tactics and reduce the risk of injury.
As the puck dropped on another NHL season on Tuesday night, kickstarting the 104th season of play, the league is well-positioned to lead the four major sports leagues out of the Stone Age and into a new frontier regarding cannabis.
Fans may recall that during the 2020 postseason, when NHL teams were forced to finish out the postseason in a bubble, reports of players accessing weed gummies for help relaxing started to leak.
The reality is that cannabis use among NHL players has never been much of a secret. If you don’t believe us, ask former Stanley Cup Winning Detroit Red Wing Darren McCarty, who opened up his own cannabis dispensaries across Michigan following a decade-plus long career of evading the league’s anti-drug program.
Major League Baseball’s rulebook could use an injection of common sense.
Rules and rulings overshadowed on-field performance in a pair of postseason games Sunday, and that’s less than ideal – especially for the Tampa Bay Rays and Houston Astros.
While the umpires on the field and replay officials in the New York command center may have very well made each call correctly by the book, that doesn’t mean MLB’s rules couldn’t benefit from some rethinking about the spirit of what they’re trying to accomplish.
For starters, the league’s ground-rule double rule needs an adjustment following a crucial moment Sunday in Boston.