Applied Sports Science newsletter – February 17, 2016

… Valentine learned the sport — and how much work was required to be good and maybe great at it — from his father, who played at Michigan State in the 1980s and then professionally overseas. Carlton Valentine still wakes up between 5 and 6 every morning to work out; he taught his sons to never let anyone else outwork them. He also made sure they had good guard skills and did ball-handling drills growing up.

Drew Valentine, two years older than Denzel, spent two seasons as a graduate assistant at Michigan State, a critical cog in his brother’s growth during his college career; now Drew is an assistant coach at his alma mater, Oakland.

Denzel Valentine feels fortunate to have both perspectives in addition to Izzo’s; he says his dad gives him the old-school basketball point-of-view, and his brother the “new” school. But perhaps the most significant contribution to the success Valentine has had as a Spartan was Drew’s commitment to helping Valentine improve his shot and his range.

Undersized and underrated, Draymond Green has become the sought-after prototype of the perfect NBA player.

… In in this second stint in the league, Beasley now serves as the experienced steady hand on the Dynamo backline. And despite the gray beard and advancing years, he’s not looking to hang his boots up anytime soon.

“I can’t lie,” Beasley said. “It’s crossed my mind a couple of times. But once this stops being fun and it starts becoming a job, then I’ll know it’s time to hang it up.

On the afternoon of Sunday, Nov. 29, Dirk Nowitzki was in Dallas, waiting to board the Mavericks’ team plane for Sacramento, when he heard the report: Kobe Bryant was retiring at the end of the season.

The news saddened Nowitzki. In part because he has long admired Bryant, often hurrying home from his own games to catch the fourth quarter of the Lakers’ West Coast feed. But also because he and Bryant are the same age, 37, and to see a peer betrayed by his body is to grapple with his own athletic mortality. Now, lying on a massage table in his suite at the Sacramento Hyatt later that night, he can’t help but think about the future. Hovering over him is Casey Spangler, the team’s massage therapist, who works on Nowitzki most days, one of many measures the 13-time All-Star uses to keep playing in this, his 18th NBA season.

PURPOSE:

To compare the effects of two repeated-sprint training programs on fitness in soccer.
METHODS:

Fifteen semi-professional soccer players (age 24 ± 4 y; body mass 77 ± 8 kg) completed 6 repeated-sprint training sessions over a two week period. Players were assigned to a straight-line (STR) (n = 8; 3-4 sets of 7 × 30-m) or change of direction (CoD) (n = 7; 3-4 sets of 7 × 20-m) repeated-sprint training group. Performance measures included 5, 10 and 20-m sprints, countermovement jump, Illinois agility and Yo-Yo intermittent recovery level 1 (YYIRTL1) performance. Internal (heart rate) and external (GPS-derived measures) training loads were monitored throughout. Data were analysed using magnitude-based inferences.
RESULTS:

Internal and external loads were higher in STR than CoD with large differences in maximum velocity (28.7%; ±90% confidence limits 3.3%), moderate differences in mean heart rates (7.0%; ±1.4%) and PlayerLoad™ (17.6%; ±8.6%), and small differences in peak heart rates (3.0%; ±1.6%). Large improvements in 5-m (STR: 9.6%; ±7.0% and CoD: 9.4%; ±3.3%), 10-m (STR: 6.6%; ±4.6% and CoD: 6.7%; ±2.2%) and 20-m (STR: 3.6; ±4.0% and CoD: 4.0; ±1.7%) sprints were observed. Large and moderate improvements in YYIRTL1 performance were observed following STR (24.0%; ±9.3%) and CoD (31.0%; ±7.5%), respectively. Between-group differences in outcome measures were unclear.
CONCLUSIONS:

Two weeks of repeated-sprint training stimulates improvements in acceleration, speed and high-intensity running performance in soccer players. Despite STR inducing higher internal and external training loads, training adaptations were unclear between training modes, indicating a need for further research.

Until a few years ago, the accepted wisdom for those looking to improve performance was just to run more, train smarter, or lose weight. Now, you might have to rethink how you run.

Last term, I ended up taking three machine learning courses, along with a couple of others. Out of all of the stuff I did last term, the biggest and best thing I did was work with a few friends on a group project. This project was: Automatic Estimation of Heart rate from Audio and Video

Now this might sound like nonsense to most people, “how can you hear my heartrate? My heart doesn’t beat that loudly! And you you can detect my heart rate from video? witchcraft!?”. In fact you would be almost right.

Several studies like this one have shown that it is completely possible. In short: Your heartbeat affects the nerve that operates your voicebox, and the change in coloration of a person’s face does indeed match a heartbeat (your face becomes more red when your heart pumps blood to it).

What motivates people to become fastidious custodians of their own health? Clearly, a medical emergency – a cancer diagnosis, heart attack, or trip to the hospital – can be a powerful motivator. However, I left my university job thinking more broadly about the science of behavior change. Can tracking basic biology create positive reinforcements for health-related behaviors?

Twenty years ago, graph paper, a pencil, and commitment were the only option. Today, however, the solution is something everyone has in their pocket, or on their wrists. Modern wearable sensors can track heart rate, calories burned, sleep patterns and so much more. The data and trends can be presented on our computers and our phones every day.

More and more devices over the last 1-2 years have begun to include the ability to record your heart rate (HR) data around the clock. No longer are you limited to just workout HR data, but now you can get it while you eat, sleep and work (and practice Valentine’s Day). But the question is how useful is that data? And what can you actually do with it? Further, does it really matter which device you use?

If you’ve been using a watch or bracelet to track your heart rate or number of steps, the Lexington-based company MC10 has news for you: It’s time to think beyond the wrist.

Wearable devices that track physiological activity have seen a surge in sales in the past several years, and last year’s release of the Apple Watch, with its built-in HealthKit tracking system, was hailed as the mainstreaming of the trend. The market for these sorts of devices is poised to grow by 18 percent in the next five years, according to a recent study by Accuray Research, and reach $33.4 billion by 2020. But the issue with these wearables remains: While people are eager to slap their new toys on their arms, one study found that a third of users stop using their trackers within six months. MC10 believes it has found a way to help fix that.

Background:

Landings in fatigue conditions are considered to be one of the factors that cause noncontact anterior cruciate ligament (ACL) injury. Additionally, it is known that fatigue alters lower extremity landing strategies and decreases the ability to attenuate shock during landing.
Purpose:

To determine characteristics of knee kinematics and shock attenuation during the landing phase of a single-leg vertical drop jump in a fatigued condition. The hypothesis was that knee kinematics during the landing phase of a single-leg vertical drop jump would demonstrate a significant difference between before and after fatigue.
Study Design:

Controlled laboratory study.
Methods:

Thirty-four college females participated in this experiment. They were randomly assigned to either the fatigue (n = 17) or control group (n = 17). The fatigue group performed the single-leg vertical drop jump before and after the fatigue protocol, which was performed on a bike ergometer. Knee kinematics data were obtained from the 3-dimensional motion analysis system. The ratio of each variable (%) was calculated, comparing the pre- to postfatigue protocol. Unpaired t tests were used to compare changes in kinematic variables between the fatigue-induced group and control group.
Results:

Peak knee flexion angular velocity increased significantly in the fatigue group (106.1% ± 8.0%) in comparison with the control group (100.7% ± 6.6%) (P < .05). However, peak knee flexion angle and acceleration had no differences between each group. Peak knee adduction/abduction angle, velocity, and acceleration also had no differences between each group.
Conclusion:

Fatigue decreased the ability to attenuate shock by increasing angular velocity in the direction of knee flexion during single-leg drop jump landing. These findings indicate the need to evaluate the ability to attenuate shock by measuring knee flexion angular velocity when fatigue is considered.
Clinical Relevance:

Measuring knee angular velocity during landings might be an important evaluation parameter in the consideration of the knee injury prevention.

Background: The evidence linking knee kinematics and kinetics during a vertical drop jump (VDJ) to anterior cruciate ligament (ACL) injury risk is restricted to a single small sample. Still, the VDJ test continues to be advocated for clinical screening purposes.

Purpose: To test whether 5 selected kinematic and kinetic variables were associated with future ACL injuries in a large cohort of Norwegian female elite soccer and handball players. Furthermore, the authors wanted to assess whether the VDJ test can be recommended as a screening test to identify players with increased risk.

Study Design: Cohort study; Level of evidence, 2.

Methods: Elite female soccer and handball players participated in preseason screening tests from 2007 through 2014. The tests included marker-based 3-dimensional motion analysis of a drop-jump landing. The authors followed a predefined statistical protocol in which they included the following candidate risk factors in 5 separate logistic regression analyses, with new ACL injury as the outcome: (1) knee valgus angle at initial contact, (2) peak knee abduction moment, (3) peak knee flexion angle, (4) peak vertical ground-reaction force, and (5) medial knee displacement.

Results: A total of 782 players were tested (age, 21 ± 4 years; height, 170 ± 7 cm; body mass, 67 ± 8 kg), of which 710 were included in the analyses. The authors registered 42 new noncontact ACL injuries, including 12 in previously ACL-injured players. Previous ACL injury (relative risk, 3.8; 95% CI, 2.1-7.1) and medial knee displacement (odds ratio, 1.40; 95% CI, 1.12-1.74 per 1-SD change) were associated with increased risk for injury. However, there was an association with medial knee displacement among the 643 players with no history of previous injury. A receiver operating characteristic curve analysis of medial knee displacement showed an area under the curve of 0.6, indicating a poor-to-failed combined sensitivity and specificity of the test, even when including previously injured players.

Conclusion: Of the 5 risk factors considered, medial knee displacement was the only factor associated with increased risk for ACL. However, receiver operating characteristic curve analysis indicated a poor combined sensitivity and specificity when medial knee displacement was used as a screening test for predicting ACL injury. For players with no previous injury, none of the VDJ variables were associated with increased injury risk.

Clinical Relevance: VDJ tests cannot predict ACL injuries in female elite soccer and handball players.

High degrees of rotational traction associated with athletic footwear can increase the risk of noncontact lower extremity injury following an unexpected neuromuscular perturbation, possibly by increasing biomechanical joint loading at the ankle and knee.

A column by Mick McCabe for the Detroit Free-Press railing against recruiting combines — those run by Rivals and the like — came to our attention today, and we’d like to break down its arguments while soliciting thoughts from our readership.

McCabe comes in hot, so let’s get right to it:

The Underwear Olympics? Those are high school football combines, and before you shell out your hard-earned money for these things, you should know the people putting them on are perpetrating a fraud on parents and players.