Applied Sports Science newsletter – July 14, 2021

… Tom: The men’s national team is one of the most ethnically diverse in sports. Not so much with the women’s team – very few women of color. That’s a reflection of the youth pipeline, dominated as it is by families paying thousands of dollars a year to clubs, starting in grade school. How do you look at that challenge?

Cindy: While I think we’re doing a better job on the boys and the men side of the game, I still think about how many are we missing out? How many people of color, whether they’re a girl or a boy, grew up feeling that soccer isn’t for them, that it’s not accessible to them? That’s a problem, so we’re doing a study to find out what the real barriers are. How do we engage (disadvantaged youth)? How do we make them see that soccer or sport in general is for them?

Part of that is due to the pay-to-play model. But there’s other issues as well, which is really why I’m excited about the study, which we plan to make public because it’s not just U.S. Soccer solving this problem. It’s all of us working together and bringing people of color not only to soccer but to every sport and to make sure that they have access and see themselves in different sports.

Background In a recent randomised controlled trial, we found that a commonly used training load management approach was not effective in preventing injuries and illnesses in Norwegian elite youth footballers.

Aim To investigate players’ and coaches’ barriers and facilitators to a load management approach to prevent injuries and illnesses and their attitudes and beliefs of load management and injuries and illnesses in general.

Methods We asked players and coaches about their views on injury risk in football, the benefits and limitations of load management in general and implementation of load management in football. The questionnaires used were based on similar studies using the Reach, Effectiveness, Adoption, Implementation and Maintenance framework.

Results We recorded answers from 250 players and 17 coaches. Most players (88%) reported that scientific evidence showing improved performance from the intervention measures is a key facilitator to completing the intervention. Similarly, coaches reported that the most important facilitator was scientific evidence that the preventive measures were effective (100%). Players reported that the coach’s attitude to preventive measures was important (86%), and similarly, 88% of coaches reported that the player’s attitude was important.

Conclusions By having a mutual positive attitude towards the intervention, players and coaches can positively contribute to each other’s motivation and compliance. Both players and coaches reported scientific evidence for load management having injury-preventive and performance-enhancing effect and being time efficient as important facilitators. [full text]

This study aimed to examine which variable, between the peak running velocity determined on the track field (Vpeak_TF) and critical speed (CS), is the best predictor of the 5-km running performance in recreational runners. Twenty-five males performed three tests to determine the Vpeak_TF, CS, and 5-km running performance on the track field, with a minimal interval of 48 h between each test. The Vpeak_TF protocol started with a velocity of 8 km⋅h–1, followed by an increase of 1 km⋅h–1 every 3 min until volitional exhaustion, which was controlled by sound signals, with cones at every 25 m indicating when the participants were required to pass the cone’s position to maintain the required velocity. The participants performed three time trials (TTs) (1: 2,600 m; 2: 1,800 m; and 3: 1,000 m) on the same day, with a 30-min rest period to determine the CS through the combinations of three (CS1,2,3) and two TTs (CS1,2, CS1,3, and CS2,3). The 5-km running performance time was recorded to determine the test duration, and the mean velocity (MV) was calculated. There was a significant difference observed between the Vpeak_TF and the MV 5-km running performance. However, no differences were found between the CS values and the MV 5-km running performance. A correlation was observed between the Vpeak_TF (R = −0.90), CS1,2,3 (R = −0.95), CS1,3 (R = −0.95), and the 5-km running performance time. Linear regression indicated that the Vpeak_TF (R2 = 0.82), CS1,2,3 (R2 = 0.90), and CS1,3 (R2 = 0.90) significantly predicted the 5-km running performance time. The CS results showed a higher predictive power for the 5-km running performance, slightly better than the Vpeak_TF. Also, CS1,2,3 and the CS1,3 presented the highest predictive power for the 5-km running performance of recreational runners. [full text]

The aim of this study was to examine the impact of two different post-match training interventions on the subsequent recovery of perceptual and biochemical parameters after the game. In a crossover design, eight sub-elite players underwent a soccer-specific training (SST) and an active recovery (AR) regimen on the second day after a match (+48 h). Muscle soreness as well as muscle damage (creatine kinase, CK), inflammatory (C-reactive protein and interleukin 6), immunological (e.g., lymphocytes, neutrophils, and monocytes), and endocrine (cortisol) markers were obtained at baseline (−72 h), immediately after (0 h), and 72 h post-match (+72 h). AR promoted a higher restoration of muscle soreness values (P = 0.004, η2p = 0.49) together with a better restoration of CK within 72 h post-match compared with SST (P = 0.04, η2p = 0.36). Conversely, no significant (P > 0.05, η2p < 0.91) differences were observed in the recovery timeframe of inflammatory, immunological, and endocrine responses between SST and AR. Overall, AR elicited a quicker muscle soreness and CK restoration compared to SST intervention at 72 h post-match. Such information provides novel evidence-based findings on the appropriateness of different recovery strategies and may aid to improve the practitioners’ decision-making process when two consecutive games are played within 3 days.

Stretchable ionic skins are intriguing in mimicking the versatile sensations of natural skins. However, for their applications in advanced electronics, good elastic recovery, self-healing, and more importantly, skin-like nonlinear mechanoresponse (strain-stiffening) are essential but can be rarely met in one material. Here we demonstrate a robust proton-conductive ionic skin design via introducing an entropy-driven supramolecular zwitterionic reorganizable network to the hydrogen-bonded polycarboxylic acid network. The design allows two dynamic networks with distinct interacting strength to sequentially debond with stretch, and the conflict among elasticity, self-healing, and strain-stiffening can be thus defeated. The representative polyacrylic acid/betaine elastomer exhibits high stretchability (1600% elongation), immense strain-stiffening (24-fold modulus enhancement), ~100% self-healing, excellent elasticity (97.9 ± 1.1% recovery ratio, <14% hysteresis), high transparency (99.7 ± 0.1%), moisture-preserving, anti-freezing (elastic at −40 °C), water reprocessibility, as well as easy-to-peel adhesion. The combined advantages make the present ionic elastomer very promising in wearable iontronic sensors for human-machine interfacing.

This paper describes the design, fabrication, and feasibility of paper-based optode devices (PODs) for sensing potassium selectively in biological fluids. PODs operate in exhaustive mode and integrate with a handheld, smartphone-connected optical reader. This integrated measuring system provides significant advantages over traditional optode membranes and other paper-based designs, by obtaining a linear optical response to potassium concentration via a simple, stackable design and by harnessing a smartphone to provide an easy-to-use interface, thus enabling remote monitoring of diseases.

Researchers at the University of Freiburg and the University of Stuttgart have developed a new process for producing movable, self-adjusting materials systems with standard 3D-printers. These systems can undergo complex shape changes, contracting and expanding under the influence of moisture in a pre-programmed manner. The scientists modeled their development based on the movement mechanisms of the climbing plant known as the air potato (Dioscorea bulbifera). With their new method, the team has produced its first prototype: a forearm brace that adapts to the wearer and which can be further developed for medical applications. This process has been collaboratively developed by Tiffany Cheng and Prof. Dr. Achim Menges from the Institute of Computational Design and Construction (ICD) and the Integrative Computational Design and Construction for Architecture Cluster of Excellence (IntCDC) at the University of Stuttgart, together with Prof. Dr. Thomas Speck from the Plant Biomechanics Group and the Living, Adaptive and Energy-autonomous Materials Systems Cluster of Excellence (livMatS) at the University of Freiburg. The researchers are presenting their results in the journal Advanced Science.

… Sweat is a particularly promising energy source because it contains a natural byproduct of anaerobic respiration—the method used by your body to get energy quickly when you exert yourself—called lactate that can be broken down by an enzyme to produce energy. However, existing devices need a lot of sweat to work, and most people don’t want to hit the gym whenever their electronics run out of power.

“The [energy] return on investment is really low,” says Lu Yin, a nanoengineer with the University of California, San Diego.

So Yin and his team turned to fingertip sweat. Our fingertips are home to the highest concentration of sweat glands on our body—even higher than in our armpits—and they make sweat constantly, regardless of whether you’re exerting yourself. We typically don’t notice this sweat because it evaporates almost instantly.

Context: Return to sport is widely utilized by sports medicine researchers and clinicians as a primary outcome of interest for successful recovery when working with young patients who have undergone anterior cruciate ligament (ACL) reconstruction (ACLR). While return-to-sport outcomes are effective at tracking progress post-ACLR, they are limited because they do not necessarily capture physical activity (PA) engagement, which is important to maintain knee joint health and reduce the risk of noncommunicable diseases. Therefore, there is a critical need (1) to describe current PA participation and measurement recommendations; (2) to appraise common PA measurement approaches, including patient-reported outcomes and device-based methodologies; and (3) to provide clinical recommendations for future evaluation.

Evidence acquisition: Reports of patient-reported or device-based PA in patients with ACL injury were acquired and summarized based on a PubMed search (2000 through July 2020). Search terms included physical activity OR activity AND anterior cruciate ligament OR ACL.

Study design: Clinical review.

Level of evidence: Level 5.

Results: We highlight that (1) individuals with ACLR are 2.36 times less likely to meet the US Department of Health and Human Services PA recommendations even when reporting successful return to sport, (2) common patient-reported PA assessments have significant limitations in the data that can be derived, and (3) alternative patient-reported and device-based assessments may provide improved assessment of PA in this patient population.

Conclusion: Clinicians and researchers have relied on return to sport status or self-reported PA participation via surveys. These approaches are not consistent with current recommendations for PA assessment and do not allow for comparison with contemporary PA recommendations or guidelines. Return to sport, patient-reported outcome measures, and device-based assessment approaches should be used in complementary manners to comprehensively assess PA participation after ACLR. However, appropriate techniques should be used when assessing PA in adult and adolescent populations.

*Brady is oldest by 4 full years
*Only one defensive player in entire league is 35: Bucs DT Steve McClendon
*Less than 10 pct of league is 30 or older
*Why did the Texans sign so many old guys?

Owners like Steve Ballmer can take the kinds of deductions on team assets — everything from media deals to player contracts — that industrialists take on factory equipment. That helps them pay lower tax rates than players and even stadium workers.

Quick, who’s the most valuable player in your favorite sport? If you’re a football fan, odds are you thought of a quarterback and not a defensive lineman; in basketball, it’s probably a high-volume shooter, not a rim protector; in baseball, it’s often a slugger, rarely a pitcher. Same in soccer, where the glory goes to players who score goals, not the ones who prevent them. The only goalkeeper ever to win the Ballon d’Or, soccer’s most prestigious award, was Dynamo Moscow’s Lev Yashin. He played his World Cup games for the Soviet Union, if that gives you an idea how long it’s been since anyone gave shot-stopping its due.

In a sport where a goal saved is roughly as good as a goal scored, it’s hard to say why the field is so heavily tilted toward shooters. Part of it could be that we haven’t had good ways to measure what keepers do. “A guy who gets a lot of clean sheets may just have a good defense,” said Brian Bilello, the president of Major League Soccer’s New England Revolution. Save percentage isn’t an ideal metric, either, since a keeper who stops a higher share of his shots on target may be facing easier shots from distance. “I would say goalkeepers are misvalued,” Bilello said.

Banning or limiting defensive shifts would be an effort to restore Major League Baseball to how it was played before offense was suffocated by analytics, according to baseball Commissioner Rob Manfred.

Speaking before Tuesday’s All-Star Game to the Baseball Writers’ Association of America, Manfred said seven-inning doubleheaders and starting extra innings with runners on second base likely will be dropped after this season.

He said extending the designated hitter to the National League could be possible, but not definite.

“I think it would be a non-radical change, but I’m not going to speculate on whether we’re going to propose it or get it,” he said.

Let’s get one thing clear here. This is not a return of England’s penalty curse. This is not England ‘reverting to type’ by losing another shoot-out. If anything, the events of the Euro 2020 final are the total opposite. Let me explain…

For a start, the (unsurprising) reaction of England coach Gareth Southgate to the Euro 2020 final defeat is unlike any of his predecessors. Every England coach whose team had preciously lost on penalties all said that the shoot-out is a lottery and can’t be practised (as did Didier Deschamps not so long ago). Southgate, who believes penalties are a trainable skill that can be improved, take the other view.