Applied Sports Science newsletter – December 16, 2015

… I’ve definitely improved a lot since last season, especially on the offensive side of the court…my post-game, my jump shot, getting more involved in the offense. This past summer, I worked a lot on my jump shot – timing, form, balance…everything I could do to work on my jumper. Let’s just say that I got a lot of shots up this past offseason! I’m getting more trust from my coaches and teammates than ever before. They trust me to make plays on the offensive end, encourage me to take shots and want me to be one of the focal points of the offense.

… Thanks in part to his surgically repaired knee, Anthony has appeared committed to playing tighter, more attentive defense along the perimeter this year. He has also made several stops as the lone defender back guarding a player who’s leading a fast break.

“Last year, he physically wasn’t able to do a lot of the things we ask our guys to do on the defensive end, and was very limited,” coach Derek Fisher said. “This year, the effort and mind-set have been there. He’s expending more energy on that end of the floor, which impacts your offense. That’s why some guys don’t like playing defense: the intensity takes away from how much you can put into your offense.”

Exercise-induced muscle fatigue has been shown to be the consequence of peripheral factors that impair the muscle fiber contractile mechanisms. Central factors arising within the Central Nervous System have also been hypothesized to induce muscle fatigue, but no direct empirical evidence that is causally associated to reduction of the muscle force generating capability has yet been reported. We developed a simulation model to investigate whether peripheral factors of muscle fatigue are sufficient to explain the muscle force behavior observed during empirical studies of fatiguing voluntary contractions, and which is commonly attributed to central factors. Peripheral factors of muscle fatigue were included in the model as a time-dependent decrease in the amplitude of the motor unit force twitches. Our simulation study indicated that the force behavior commonly attributed to Central Fatigue could be explained solely by peripheral factors during simulated fatiguing sub-maximal voluntary contractions. It also revealed important flaws regarding the use of the interpolated twitch response from electrical stimulation of the muscle as a means for assessing Central Fatigue. Our analysis does not directly refute the concept of Central Fatigue. However, it raises important concerns about the manner in which it is measured, about the interpretation of the commonly accepted causes of Central Fatigue, and questions the very need for the existence of Central Fatigue.

… 1. Running is a sport of adaptation. When you run, you stress your joints, muscles and aerobic system. Between workouts, your body recovers and adapts to the load applied during your run so that it will be better prepared for your next run.

What’s one of the easiest yet more profound ways to improve your athletic performance? According to Dr. Kirk Parsley, MD, and NYT bestselling author Robb Wolf, getting consistent deep sleep could allow you to make enormous gains in both health and athletic capacity.

… As we cope with struggles in our own lives and witness other people’s struggles unfold in the news, a common response is to search for an underlying significance that might make our devastation more bearable. This process of making meaning out of misery can be beneficial. For example, cancer patients who derive meaning from their medical experiences have greater psychological adjustment. Likewise, following the death of a family member, people who make sense of their loss and even find benefits in it experience less distress. The psychiatrist and Holocaust survivor Viktor Frankl wrote extensively about this process after observing that his fellow inmates in concentration camps were more likely to survive the horrific conditions if they held on to a sense of meaning.

To understand how this process is possible, researchers have studied a fascinating phenomenon called post-traumatic growth.

Little if any research has examined the variability in time to exhaustion (TTE) during submaximal treadmill running. This study investigated the test-retest reliability of submaximal treadmill TTE as a measure of endurance capacity. 16 endurance-trained males (n=14) and females (n=2) completed a run to exhaustion at 70% V?O2max (T1) and repeated the same run 3 weeks later (T2). At 30-min intervals during each run, expired gas, heart rate (HR) and ratings of perceived exertion (RPE) were collected. Mean±SD TTE was 96±20?min in T1 vs. 101±29?min in T2 (P=0.3). The mean±95% confidence intervals (CI) of the coefficient of variance (CV) was 5.4% (1.4–9.6). The average intraclass correlation coefficient (±?95% CI) was 0.88 (0.67–0.96) between trials. The respiratory-exchange ratio was not different between trials, T1: 0.87±0.1 and T2: 0.89±0.1 (P>0.05) and neither was total whole-body carbohydrate oxidation (2.1±0.4?g·min?1 and 2.3±0.6?g·min?1), fat oxidation (0.6±0.2?g·min?1), HR (178±8 and 175±7?beats·min?1) or RPE (17±3 and 16±3). These results suggest that use of prolonged treadmill-based TTE can be a reliable research tool to assess human endurance capacity in aerobically-trained men and women.

When you get mysteriously ill, how do you diagnose what’s up? If you’re at home, you might have a thermometer to help identify your illness, but not much else. Even your general practice doctor is limited by the tools they have to hand. To find out, you have to go to hospital – where complicated machinery is available, for blood tests, scans and more. Unfortunately, not everybody has that access.

That’s why Anita Goel of the company Nanobiosym decided to invent a ‘tricorder’ – in the same vein as the multipurpose medical tool used in Star Trek – that has the potential to transform healthcare itself.

Treating sick people with healthy blood is nothing new. But a new biotech company wants to treat disease by transforming red blood cells into tiny medicine delivery pods, using genetic engineering techniques that have helped turn other human cells into cutting-edge cancer therapies.

The startup is called Rubius Therapeutics, and it’s announcing today a $25 million investment from Flagship Ventures, a Cambridge, MA-based venture group.

The interplay of health and design isn’t new. In 1857, Nurse (and Data Scientist) Florence Nightingale used design principles to illustrate the casualties of soldiers in the Crimean War and changed national policy.

Nightingale showed that soldiers weren’t dying mainly on the battlefield, but instead they were dying in the hospitals due to the poor sanitary conditions there. Nightingale used this now famous diagram to influence hygiene practices in military hospitals, which resulted in lower mortality rates. The kind of design that Nightingale used can be thought of as, “Design to improve understandability.”

Background: Anterior cruciate ligament (ACL) injury rates are affected by frequency and level of competition, sex, and sport. To date, no study has sought to quantify sport-specific yearly risk for ACL tears in the high school (HS) athlete by sex and sport played.

Purpose: To establish evidence-based incidence and yearly risk of ACL tears in HS athletes by sex for sports performed at the varsity level across the majority of US high schools.

Study Design: Meta-analysis.

Methods: PubMed, EMBASE, and Cochrane Central Register of Controlled Trials were searched to identify all articles reporting ACL tears per athletic exposure in HS athletes. ACL injury incidence rates (IRs) by sex and sport were calculated via meta-analysis. State athletic association guidelines were used to determine the number of exposures per season to calculate yearly risk of ACL tears.

Results: The search recovered 3779 unique articles, of which 10 met our inclusion criteria, for a total of 700 ACL injuries in 11,239,029 exposures. The IR was 0.062 injuries per 1000 exposures (95% CI, 0.058-0.067). Although more injuries were recorded in males than females, females had a higher rate of injury per exposure (relative risk, 1.57; 95% CI, 1.35-1.82). Relative risk was highest in basketball (3.80; 95% CI, 2.53-5.85) and soccer (3.67; 95% CI, 2.61-5.27). While boys’ football had the highest number of ACL injuries at 273, girls’ soccer had the highest IR (0.148; 95% CI, 0.128-0.172). In girls, the highest injury risks per season were observed in soccer (1.11%; 95% CI, 0.96%-1.29%), basketball (0.88%; 95% CI, 0.71%-1.06%), and lacrosse (0.53%; 95% CI, 0.19%-1.15%). In comparison, the highest risks for boys were observed in football (0.80%; 95% CI, 0.71%-0.91%), lacrosse (0.44%; 95% CI, 0.18%-0.90%), and soccer (0.30%; 95% CI, 0.22%-0.41%).

Conclusion: There is an approximately 1.6-fold greater rate of ACL tears per athletic exposure in HS female athletes than males. However, there is significant risk in both sexes, particularly in high-risk sports such as soccer, football, basketball, and lacrosse. Knowledge of sport-specific risk is essential for future injury reduction programs, parent-athlete decision making, and accurate physician counseling.

OBJECTIVE:

To develop and validate a concise survey that will identify athletes who possess elevated injury risk.
DESIGN:

Cohort study.
SETTING:

National Collegiate Athletic Association Division I athletic program.
PARTICIPANTS:

Cohorts of 188 and 146 college athletes who participated during successive academic years.
ASSESSMENT OF RISK FACTORS:

The first cohort provided responses to 4 joint-specific outcome surveys that were related to subsequent time-loss injury occurrence. Receiver operating characteristic analysis identified survey items that provided best discrimination, which were combined with a negative life event stress item to create a new 10-item survey. The second cohort provided responses to the new survey, which were converted to a 0 to 100 score.
MAIN OUTCOME MEASURES:

Construct validity was assessed through documentation of time-loss injuries sustained during the preceding 12 months and predictive validity was assessed through prospective documentation of sport-related sprains and strains. Cronbach alpha was calculated to assess internal consistency.
RESULTS:

Each of the outcome survey items used to develop the new survey demonstrated much greater specificity than sensitivity. Both the retrospective and prospective receiver operating characteristic (ROC) analyses identified scores of 96 and 88 as cut-points that provided good discrimination between injured and noninjured cases. The area under the curve was 0.69 (P < 0.001) for the retrospective analysis and 0.62 (P = 0.016) for the prospective analysis. Cronbach alpha was 0.89 (90% CI, 0.86-0.91).
CONCLUSIONS:

Self-reported effects of previous injury may be one method to efficiently identify athletes who possess elevated injury risk, and subsequently deliver preventive interventions, thereby providing an alternative method to time-intensive functional testing.

Background: Performance outcomes and return-to-play data have been reported after anterior cruciate ligament (ACL) injuries in professional football and basketball, but they have rarely been reported in professional hockey.

Hypothesis: The hypothesis was that performance after ACL reconstruction would be comparable to prior levels of play in a series of National Hockey League (NHL) players.

Study Design: Case series; Level of evidence, 4.

Methods: The NHL Injury Surveillance System (ISS) was utilized to identify all players with an ACL injury between 2006 and 2010. Medical staff members for all NHL teams were surveyed regarding these injuries. The medical staff completed a questionnaire for each injury, and statistics were analyzed using multiple analyses of variance to compare outcomes, performance, and the complication rate. A control group was identified and matched based on performance, career length before injury, age, height, and weight.

Results: There were 47 players identified by the NHL ISS. There were 3 goalies, 8 defensemen, and 36 wings or centers. The average age of these players was 27.69 years. The average length of time played after the injury was 2.8 years, which was less than that of the control group (4.4 years) (P = .004). The presence of a meniscal injury was associated with a decreased length of career compared with the control group (P = .012) and with patients with an isolated ACL injury (P = .002). For wings and centers, the number of games played decreased from 71.2 to 58.2 in the first full season after the injury (P = .05) and to 59.29 in the second season (P = .03). In the first season after the injury, for forwards and wings, assists and total points decreased from 20.3 and 35.2 to 13.8 (P = .005) and 25.9 (P = .018), respectively. In the second season after the injury, assists and goals decreased to 10.0 (P = .002) and 10.0 (P = .013), respectively. Compared with controls, the per-season averages of goals (P = .001), assists (P = .010), and total points (P = .004) decreased. Four players (8.5%) had subsequent failure of reconstruction, and there was a total reoperation rate of 20%. Five players (10.6%) did not return to play, and 4 (8.5%) were unable to return to play for a full season.

Conclusion: Most players are able to return to play in the NHL after an ACL injury. However, career length and performance may be significantly decreased compared with controls. This may represent a more severe initial injury, and more focused return-to-play pathways may identify barriers to return to play.

… As you might expect, many of these kits will involve the testing of blood. “In blood you can detect just about everything that you’ve eaten, or that’s going on in your body,” says Guy Carpenter, reader in oral biology at Kings College London.

But it’s possible that technology will emerge to measure other excretions, says George Preti at the Monell Chemical Senses Center in Philadelphia. He is currently investigating what your earwax can say about you. Unlike blood, earwax is a fatty substance, which means certain molecules may concentrate there and be easier to detect than in more watery fluids. “If you have a certain group of metabolites that like to dissolve in lipids (fats), we may be able to look at them in earwax,” Preti says. [video, 3:40]