Applied Sports Science newsletter – August 2, 2017

… Mariota has been fully cleared physically, but the toughest recovery for these major injuries is often mental. Trust is often the last thing to return, but Mariota said he has overcome that hurdle, as well.

“When you go through this process, you want to get to this point,” Mariota said. “The process getting here is tough, but now that I’m here, it’s kinda nice to enjoy it and be out there with the guys.”

… “It was always a case that wherever my job was, that was my home,” Schweinsteiger said. “Of course, when I touch down in Germany and I’m close to my parents’ house, you feel like you grew up there, you were born there. You always say, ‘That’s my home.’ But I always say that Chicago is my home place now.”

“You have your spots,” he added. “You just have to find them.”

Schweinsteiger’s Chicago embrace has not been lost on his teammates, and together this season they have engineered one of Major League Soccer’s biggest turnarounds. The Fire, the league’s worst team the last two years, have spent time in first place this season and have the league’s second-best record heading into Wednesday night’s M.L.S. All-Star Game at Soldier Field. Last week, Schweinsteiger won an online vote that will see him serve as captain for the league’s team against Real Madrid.

… many Huskers noted how the strength and conditioning staff cranked up these summertime workouts and tweaked the routine with one goal in mind – finishing.

No longer did players show up for 6 a.m. workouts and go home by midmorning. They had to stick around for afternoon running, too.

“It could be 98 outside and we’d be out there doing a grueling workout,” Weber said. “We were really focused on finishing. That’s something I think we need to get better at in being a better football team.

I’m from Louth, with a passion for sport. Despite (or because of!) this I had never seen a game of hurling until I was a wide-eyed 17 year old leaving home for college in Waterford, on a bus passing through Kilkenny. This might sound surreal to some, but despite there being hurling teams in Louth it just isn’t part of the culture and identity of the county as much as it is in other counties.

What influences what we play?

Lots of sociological and environmental factors influence what and how we play, all worthy of a blog in themselves (e.g. culture, environmental issues, what your parents/family played, socioeconomic factors, peer influence, gender, ethnicity, education)…all in good time. Place of birth is another factor that can influence not only what we play but how likely we are to succeed in that sport. As in the example above, where you are born can dictate what sport you’re likely to play (it will generally be the sport that’s valued in that setting, your school values it and wants to succeed in it so resources are found for it, clubs have a stronghold in the community, your parents/extended family/local role-models played it (often down to the specific position you want to play… I’m looking at you goal-keepers from Donegal!!) and can influence how successful you are (and organically drive these ‘hothouses’ of talent development, like the Skibereen rowers or NI golfers).

… When the new system was up and running, PSV and AZ rolled it out to their junior teams. “The academy is the laboratory of the club,” says Marijn Beuker, head of performance and development at AZ. Younger players are also more teachable than their more established elders. “The most tactical phase to train the players is between 14 and 17,” van Agt says.

The Football IntelliGym looks a little like a soccer game with the players switched out with blue and red spaceships. A user pilots one of those ships around a rectangular arena, dragging teammates into position, and passing and shooting a yellow hexagon. Players are challenged to track multiple objects and anticipate movement. And as the user succeeds or fails, the drills adapt.

Beuker believes that smarter players will free players from rigid formations and make soccer more exciting. “Tactics basically means that I tell you what to do,” he says. “The problem is that that’s not football. In general, that’s not how people get creative.”

The main objective of this research was to evaluate the efficacy of intermittent hypoxic training (IHT) on anaerobic and aerobic capacity and swimming performance in well-trained swimmers. Sixteen male swimmers were randomly divided into a hypoxia (H) group (n = 8), which trained in a normobaric hypoxia environment, and a control (C) group (n = 8), which exercised under normoxic conditions. However, one participant left the study without explanation. During the experiment group H trained on land twice per week in simulated hypoxia (FiO2 = 15.5%, corresponding to 2,500 m a.s.l); however, they conducted swim training in normoxic conditions. Group C performed the same training program under normoxic conditions. The training program included four weekly microcyles, followed by three days of recovery. During practice sessions on land, the swimmers performed 30 second sprints on an arm-ergometer, alternating with two minute high intensity intervals on a lower limb cycle ergometer. The results showed that the training on land caused a significant (p<0.05) increase in absolute maximal workload (WRmax) by 7.4% in group H and by 3.2% in group C and relative values of VO2max by 6.9% in group H and 3.7% in group C. However, absolute values of VO2max were not significantly changed. Additionally, a significant (p<0.05) increase in mean power (Pmean) during the first (11.7%) and second (11.9%) Wingate tests was only observed in group H. The delta values of lactate concentration (ΔLA) after both Wingate tests were significantly (p<0.05) higher in comparison to baseline levels by 28.8% in group H. Opposite changes were observed in delta values of blood pH (ΔpH) after both Wingate tests in group H, with a significant decrease in values of ΔpH by 33.3%. The IHT caused a significant (p<0.05) improvement in 100m and 200m swimming performance, by 2.1% and 1.8%, respectively in group H. Training in normoxia (group C), resulted in a significant (p<0.05) improvement of swimming performance at 100m and 200m, by 1.1% and 0.8%, respectively. In conclusion, the most important finding of this study includes a significant improvement in anaerobic capacity and swimming performance after high-intensity IHT. However, this training protocol had no effect on absolute values of VO2max and hematological variables.

The importance of sleep cannot be understated in terms of recovery. Sleep plays a critical role in not only recovery and on-field performance, but in all aspects of daily living. With new technology and recovery tools continuing to surface in recent years, it is important for coaches to help athletes see the big picture and understand how imperative sleep is toward their recovery and performance.

Understanding the stages of sleep is necessary when discussing the quality of sleep, one is getting. The stages of a sleep cycle can be broken down into Non-Rapid Eye Movement (NREM) and Rapid Eye Movement (REM)[1]. When one first begins to fall asleep, NREM sleep kicks in. NREM has 4 Stages; with stages 1 and 2 considered “light sleep” and stages 3 and 4 considered “deep sleep.” Stages 3 and 4 are considered the most crucial stages of sleep, as this is the time where the body is in full-recovery mode, particularly during stage 4, where several growth factors are released for cellular repair1. REM sleep, or the “dream stage”, occurs after the deep sleep stage1. During REM, the brain is active with low amplitude, high frequency waves, and there is a disconnect between brain and body. This allows the body to remain in a state of total relaxation, thus allowing for maximal recovery. Upon the completion of REM sleep, the body starts another cycle again. Each cycle typically lasts around 90 minutes, and one may go through 4 or 5 stages of sleep in a typical night.

According to Wright et al., subjects who received regular nightly sleep between 7-8 hours and up to 10 hours showed improved alertness and overall vigilant performance[2]. Comparatively, subjects who slept less than 7 hours showed diminished cognitive function and optimal levels of alertness during activity2. Given the incredible demands of a baseball season, it would be unrealistic to assume players would be able to get 7-8 hours of quality sleep each and every night and not suffer some sort of sleep debt at some point.

Background:

Anterior cruciate ligament (ACL) tear is a common injury in sports and often occurs during landing from a jump.
Purpose:

To synthesize the evidence on the effects of injury prevention programs (IPPs) on landing biomechanics as they relate to the ligament, quadriceps, trunk, and leg dominance theories associated with ACL injury risk.
Study Design:

Meta-analysis.
Methods:

Six electronic databases were searched for studies that investigated the effect of IPPs on landing task biomechanics. Prospective studies that reported landing biomechanics at baseline and post-IPP were included. Results from trunk, hip, and knee kinematics and kinetics related to the ACL injury theories were extracted, and meta-analyses were performed when possible.
Results:

The criteria were met by 28 studies with a total of 466 participants. Most studies evaluated young females, bilateral landing tasks, and recreational athletes, while most variables were related to the ligament and quadriceps dominance theories. An important predictor of ACL injury, peak knee abduction moment, decreased (P = .01) after the IPPs while other variables related to the ligament dominance theory did not change. Regarding the quadriceps dominance theory, after the IPPs, angles of hip flexion at initial contact (P = .009), peak hip flexion (P = .002), and peak knee flexion (P = .007) increased, while knee flexion at initial contact did not change (P = .18). Moreover, peak knee flexion moment decreased (P = .005) and peak vertical ground-reaction force did not change (P = .10).
Conclusion:

The exercises used in IPPs might have the potential to improve landing task biomechanics related to the quadriceps dominance theory, especially increasing peak knee and hip flexion angles. Importantly, peak knee abduction moment decreased, which indicates that IPPs influence a desired movement strategy to help athletes overcome dangerous ligament dominance loads arising from lack of frontal plane control during dynamic tasks. The lack of findings for some biomechanical variables suggests that future IPPs may be enhanced by targeting participants’ baseline profile deficits, highlighting the need to deliver an individualized and task-specific IPP.

Inflammation biomarkers may help doctors diagnose chronic fatigue syndrome (CFS), a poorly-understood condition in which people feeling continually exhausted. These biomarkers could also give new clues to what causes the condition, and how to treat it.

The biomarkers were discovered when a team of researchers screened the blood of 192 people with chronic fatigue syndrome for cytokines – substances used by the immune system to control inflammation. The team compared the levels of 51 different cytokines in the people with CFS and 392 people who didn’t have the condition, and found that 17 cytokines rose in tandem with how bad a person’s CFS was.

“These 17 go up by various degrees in a straight line with severity,” says José Montoya, of Stanford University.

Maintaining stability under dynamic conditions is an inherent challenge to bipedal running. This challenge may impose an energetic cost (Ec) thus hampering endurance running performance, yet the underlying mechanisms are not clear. Wireless tri-axial trunk accelerometry is a simple tool that could be used to unobtrusively evaluate these mechanisms. Here, we test a cost of instability hypothesis by examining the contribution of trunk accelerometry-based measures (tri-axial root mean square, step and stride regularity, and sample entropy) to inter-individual variance in Ec (kcal.km-1) during treadmill running. Accelerometry and indirect calorimetry data were collected concurrently from 30 recreational runners (16 men; 14 women) running at their highest steady-state running speed (80.65 ± 5.99% VO2 max). After reducing dimensionality with factor analysis, the effect of dynamic stability features on Ec was evaluated using hierarchical multiple regression analysis. Three accelerometry-based measures could explain an additional 10.4% of inter-individual variance in Ec after controlling for body mass, attributed to anteroposterior stride regularity (5.2%), anteroposterior RMS ratio (3.2%), and mediolateral sample entropy (2.0%). Our results lend support to a cost of instability hypothesis, with trunk acceleration waveform signals that are 1) more consistent between strides anteroposterioly, 2) larger in amplitude variability anteroposterioly, and 3) more complex mediolaterally, are energetically advantageous to endurance running performance. This study shows that wearable trunk accelerometry is a useful tool for understanding the Ec of running, and that running stability is important for economy in recreational runners.

… Triathletes are notorious for pushing through pain and dysfunction in a quest to continue training or make it to a big race, so when can you opt to push through, and when should you back off?

The following rules, taken from a recent article in the journal Current Sports Medicine Reports, aim to give endurance athletes, and the physicians that treat them, a tool to assess pain with exercise.

Musculoskeletal injury (MSI) data typically are obtained from medical chart-review (MCR) or injury self-reports (ISR). MSI incidence may be under-counted if only one source is utilized, as MCR will not capture MSI for which medical care was not sought, and ISR may be affected by issues with recall.
OBJECTIVES:

The purposes of this study were to determine MSI incidence from two sources (MCR, ISR) and to estimate the incidence, after accounting for the under-counting in both sources, among a sample of U.S. Army soldiers.
DESIGN:

Descriptive cross-sectional study.
METHODS:

The estimated cumulative incidence during a one-year period was calculated from the two sources of MSI data using a novel statistical analysis (capture-recapture-CRC).
RESULTS:

MSI data were available for 287 soldiers (age: 27.5±6.3years (mean±standard deviation)). The one-year cumulative incidence of MSI was 17.8% (MCR), 19.5% (ISR), and 54.0% (CRC). CRC analysis showed that there was under-counting from both sources of data and the percent of CRC estimated MSI observed were 32.9% (MCR), 36.1% (ISR), and 57.4% (MCR and ISR combined). When analyzed by MSI type, percent of CRC estimated MSI counted from both sources was highest (75.0%) for fracture, followed by sprain (53.8%), strain (43.8%), and pain/spasm/ache (35.8%).
CONCLUSIONS:

There was under-counting of MSI from both sources of data, and the under-counting varied by MSI type. There is a need for further investigation of the relative benefits of various sources of MSI data and the application of the capture-recapture analysis in military populations.

… I’ll give you the nut here in case you don’t want to read all 2,000 words on powdered cheese. Phthalates are probably a problem in our food system, but macaroni and cheese is not a unique problem, and if it’s one of the few highly processed foods that you eat, risk of phthalate toxicity is as close to zero as possible.

Some research has found that high phthalate exposure can have negative health effects—for example, some people with high levels in their bodies have increased rates of hypertension and insulin resistance—but never has a case of phthalate toxicity been linked specifically to eating macaroni and cheese.

The mac-and-cheese analysis described in the Times story looked for phthalates in processed cheeses, and it found them. It reported absolute levels—e.g. 940 micrograms of phthalates per kilogram of powdered cheese. What does that mean? How much of it stays in my body? How much macaroni would I have to eat to put myself at risk? Even though these questions are unaddressed, the conclusion of the report makes a huge leap: “Action should be taken to eliminate phthalates in any food products.”

… In a low-sample sport like football, we need to wring every little bit of info from every datapoint, so it is unconscionable to start analysis by halving the sample size. Fortunately, the analytics community appear to have recognized that collectively, and I have not seen many repeatability studies recently. Lastly, Sam’s work is closest in spirit to what follows, but since it was done without accounting for chance quality (ie. xG), we see poacher types topping his list (and Messi; there’s always Messi), in large degree due to their chances being best on average rather than due to individual ability.

My own answer to the finishing skill question is that it not only obviously exists, but it also leaves a measurable trace in small samples of shots. In fact, I was able to show that for many players, including superstars as well as relative unknowns, the probability that they are above-average finishers is very high. Furthermore, even if estimation of the skill of individual players is fraught with uncertainty, quantifying this uncertainty is not only part of our job as analysts, but can itself be an essential contribution, allowing the decision-makers to consume model results in line with their appetite for risk.

The NFL continues to become more reliant on passing plays. Last season quarterbacks set a record for most throws per game (35.7) with an average passer rating of 87.6, second-highest in league history. The best passing teams also represented their conference in the Super Bowl — the Atlanta Falcons and champion New England Patriots ranked No. 1 and No. 2, respectively, for passer rating during the regular season.

The teams that protected their quarterback the best were also among the more successful squads in the NFL. The Patriots allowed a 4.7 percent sack rate after adjusting for down, distance and opponent, the sixth-best performance in 2016, per Football Outsiders. Their AFC conference championship game opponents, the Pittsburgh Steelers, ranked fourth (4.1 percent). The NFC conference runner-up Green Bay Packers were well above average (11th at 5.5 percent — the league average is 6.1 percent).

The lesson here: It is more critical than ever for an NFL franchise to build an effective pass rush.