Applied Sports Science newsletter – September 12, 2019

… He was a pickup basketball legend, a Ping-Pong wizard, an obsessive worker who threw wherever, whenever and to whomever he could and who nearly changed positions after a year.

… In a whirlwind 14 months, Mertesacker has, so far, withstood all the long balls that have been punted in his direction. His passion for the wellbeing of the club’s youngsters shines through, as does his eagerness to see the first team delivering on their potential. After a period of flux, it feels like stability has been found and progress is being made.

Fresh from reading the World Cup winner’s newly translated autobiography ‘Big Friendly German’, Arseblog News sat down with the World Cup winner to see how his work at the Academy is coming along.

… “The sprint distances and high-intensity runs are more in English football than the rest of Europe,” [Chris Domogalla] explains. “From my experience, that’s because England has more counter-attacks and teams chasing the second ball.

The Premier League has been another level up again.

“What we had already worked out from the stats was that the number of high-intensity sprints was more in the Premier League than we had been used to during our two seasons in the Championship. This was something we clearly needed to be prepared for.

“As I say, you never really understand it until you’ve experienced it and it was a shock in those first 45 minutes against Liverpool, but we’re adapting.

Human running is inefficient. For every 10 calories burned, less than 1 is needed to maintain a constant forward velocity – the remaining energy is, in a sense, wasted. The majority of this wasted energy is expended to support the bodyweight and redirect the center of mass during the stance phase of gait. An order of magnitude less energy is expended to brake and accelerate the swinging leg. Accordingly, most devices designed to increase running efficiency have targeted the costlier stance phase of gait. An alternative approach is seen in nature: spring-like tissues in some animals and humans are believed to assist leg swing. While it has been assumed that such a spring simply offloads the muscles that swing the legs, thus saving energy, this mechanism has not been experimentally investigated. Here, we show that a spring, or ‘exotendon’, connecting the legs of a human reduces the energy required for running by 6.4±2.8%, and does so through a complex mechanism that produces savings beyond those associated with leg swing. The exotendon applies assistive forces to the swinging legs, increasing the energy optimal stride frequency. Runners then adopt this frequency, taking faster and shorter strides, and reduce the joint mechanical work to redirect their center of mass. Our study shows how a simple spring improves running economy through a complex interaction between the changing dynamics of the body and the adaptive strategies of the runner, highlighting the importance of considering each when designing systems that couple human and machine.

… A recent study by Rush University and Northwestern University shows many sleep trackers may actually worsen insomnia.

Wrist-worn trackers don’t even track sleep accurately, especially for people with serious sleep disorders. Your movement in bed or heart beat does not necessarily correlate to how well you sleep. One of the only accurate ways to track is by capturing brain activity via electroencephalography (EEG) sensors, which until recently could only be achieved in a sleep clinic.

To deploy EEG outside of the clinic effectively you need a hardware and software solution that accurately tracks sleep activity through brain activity. Heart rate, respiration and motion are useful, but in addition to EEG. You need to provide relaxation techniques driven by biofeedback. Digital coaching based on cognitive behavioral therapy for insomnia (CBTi) – the only recognized treatment for insomnia — should be a component.

… “This year is a chance to redefine what Nebraska volleyball is, with us being so close last year,” said [Lauren] Stivrins, a junior middle from Scottsdale, Arizona. “It’s easy to take where we were last year and grow from it and learn from it.

“I think that it’s super-cool that the girls we have right now are so young, but they go after it, and as you see, they don’t give up. Yeah, we have a lot of things to work on, because we are young, but I think this team is going to go a long way.”

Purpose: The aim of this study was to examine the influence of long-term whole-body electromyostimulation (WB-EMS) training in addition to standard ice hockey training in the following areas: shot speed, counter-movement-jump (CMJ) height and power, 10 m-sprint, isokinetic maximum force at 60 and 300°/s of the knee extensor muscle and subjective performance. The purpose was further to check, whether competitive status influenced the extent of response to WB-EMS and whether WB-EMS would hypothetically be a suitable method to reduce injury rate.

Methods: Thirty male amateur ice hockey players participated in this study. They were divided into two cross-over groups (Group A and Group B). EMS sessions were carried out once a week for 12 weeks for each group with a subsequent 4 week EMS pause. The sessions consisted of 20 min electromyostimulation with 150 contractions (4 s duration, 85 Hz). Shot speed of slap shot was measured with Sportradar 1503. Jumping ability was determined with a ground reaction force platform (GRFP). Sprint time for 10 m skate was recorded using an infrared photo sensor. Isokinetic force of the knee extensor muscle was detected with Isomed 2000 at two different angular velocities (60 and 300°/s) and the subjective performance was collected using a questionnaire.

Results: After 12 weeks of WB-EMS training jumping power increased significantly for the WB-EMS groups by 5.15%, 10 m skating time decreased significantly by 5%, and maximum isokinetic force at 300°/s increased significantly by 7% (all p < 0.05). In contrast post training shot speed showed no significant change. Isokinetic torque at 60°/s and vertical jump height were collected as secondary variables and showed increases of 5.45 and 15.15%, respectively. After finishing the WB-EMS and continuing the normal training, it was shown that the training effect regressed. Conclusion: This study demonstrated that WB-EMS training significantly decreased 10 m skating time and increased jumping power and maximum isokinetic force at 300°/s. We conclude that with additional WB-EMS training, an increase in performance might also be achieved for athletes in lower leagues. Due to the higher training potential of leisure athletes, the effect is probably even more pronounced than would be expected for competitive athletes. [full text]

András Hegyi is a final-stage Ph.D. student working at the Neuromuscular Research Center at the University of Jyväskylä in Finland. His Ph.D. work focuses on regional and intermuscular hamstrings EMG activity in different hamstring exercises and in running. One of the four studies included in this project was awarded a Young Investigators Award by the European College of Sport Science in 2017. Hegyi is interested in improving biomechanical methodologies to assess hamstrings to further understand hamstring muscle function and injury mechanisms.

Freelap USA: EMG is very important to sport science, but it requires careful interpretation. Can you explain why your technique differs from conventional surface EMG?

András Hegyi: As I tend to say, friends do not let friends believe in conventional EMG. When using conventional surface EMG on hamstring muscles, usually one pair of electrodes is placed over the mid-region of each muscle to estimate the activity of each hamstring muscle. However, this approach ignores regional (i.e., proximal-distal) differences in muscle activation.

… In recent years, a number of top sportswomen have talked about the impact of their menstrual cycle on their training and performance.

British tennis player, Heather Watson attributed her first round loss at the 2015 Australian Open to period symptoms, including dizziness and nausea, while British Olympic athlete Eilish McColgan believes her period contributed to a hamstring injury last year.

Research from 2016 shows that more than half of elite female athletes say that hormonal fluctuations during their menstrual cycle hampered their training and performances.

In an attempt to identify some future trends, we asked 20 baseball players, coaches, scouts, trainers and front office officials a simple question: “What is a technology that doesn’t currently exist, but would significantly impact baseball if it could be invented?”

Some of the answers were extremely practical. Some were fanciful. Here’s a selection of some of the most interesting answers on where baseball could be headed.

As businesses turn to machine learning to automate processes, questions have been raised about the ethical implications of computers making decisions. How do we address the potential for bias? What’s less talked about, but equally important, is the topic of human bias as it relates to analytics and business decision making. Human bias can enter the analytics process every step of the way. As business decision-makers start looking to predictive analytics for specific advice on what action to take next, it’s important that data and methods are leveraged as objectively as possible. The responsibility of monitoring human bias in analytics is a great one, and it all starts with the people building models from the ground up: data scientists.

As a data scientist navigating human bias in analytics every day, here are three areas I focus on to manage bias throughout the process—from evaluating the initial request and collecting information to building the model and mining for insights.

… The relationship between analyst and coach is melding further with the dawn of league-wide player-tracking data. Eagles owner Jeffrey Lurie predicted in 2016 that this radio frequency identification (RFID) technology would “revolutionize the sport in the long run” and made sure his team was well-positioned to handle the flood of information that hit the NFL as the league released two years’ worth of game data last spring.

Since 2014, the NFL has worked with Zebra Technologies to outfit its stadiums with RFID technology that tracks and records the real-time position and movement of all players using a chip embedded under their shoulder pads.

The Eagles were first in line to have the corresponding technology installed in their practice facility in 2014 — only a third of the league has followed suit in the five years since — and built up an already-robust analytics department to decode and weaponize the information that has been captured. The Eagles are one of only a few teams applying that information to help shape game plans and strategy, according to Zebra vice president of sports business development John Pollard.

With the physical demands of playing growing more and more intense, it’s become increasingly important to rest players and to work on preventing injuries. These days, all medical departments in the Bundesliga are highly focused on working individually with each player in the squad. Blood tests are conducted on a regular basis, in order to determine how fit each player is.

Lowering the burden in training sessions and allowing players to rest is a trend that’s here to stay. The logic behind these measures is simple: if your best players are available when it really matters, your team is more likely to succeed.

This study examined the temporal effects of technical fouls on the performance of the fouling and opposing teams in elite basketball games. A sample of 80 technical fouls was collected from 65 international games. The fouls were charged either to players on court or to the bench players/coaching staff. Performance measures considered were the points scored (during 1, 3, and 5 ball possessions), fouls received, violations, and turnovers during 5 ball possessions before and after a technical foul was called. Data were also obtained on several contextual variables. The results showed that the opposing team scored slightly more points compared to the fouling team during 1 ball possession before and after a foul was charged to the coach/bench personnel (F=5.934; p=0.019; ES=0.11). The results also showed that both types of technical fouls are generally positive for the opposing team (mid-term effects) and for the fouling team only during the short-term performance (points scored after 1 ball possession). Furthermore, significant differences between teams were found when comparing the fouls received, with the opposing team receiving more fouls after both types of technical fouls (F=5.364; p<0.001; ES=0.50 and F=26.350; p<0.001; ES=0.35). However, the gender and contextual variables had no significant effect on any of the performance measures. The results highlight the positive short-term (1 ball possession) and the adverse mid-term (5 ball possessions) strategic effect of technical fouls for the fouling team, and call for coaches and practitioners to design specific training scenarios that involve tactics and strategies to avoid a negative performance immediately after the technical foul.