Applied Sports Science newsletter – February 22, 2016

So far, the cautious approach has worked for New Orleans Pelicans point guard Jrue Holiday.

After a stress reaction in his right leg forced the point guard to miss 42 games last season, Holiday, who missed 48 games two seasons go with a stress fracture in the same leg, was put on a strict minutes limit to start the season. The restriction also kept him out of one end of back-to-back games until the end of December.

Holiday has shined since, with averages of 18.3 points and 7.1 assists per game after the new year while coming off the bench, a role he said he prefers because of the rhythm he can find in longer stretches without being subbed out. But the seventh-year guard admitted on Saturday that he still worries about possible setbacks.

Whether it was wise for the Dallas Mavericks to give shooting guard Wesley Matthews a max contract months after he ruptured his left Achilles tendon is debatable, to put it politely.

The Mavs certainly aren’t getting their money’s worth right now. They must get much better bang for the buck from their highest-paid player to have any hope of being more than first-round fodder — and perhaps even to make the playoffs.

Before Friday night’s game, Gregg Popovich was asked what he looks for in a job candidate with the Spurs.

Earlier in the week, assistant general manager Sean Marks became the Nets’ general manager. The Spurs are one of the most successful organizations in professional sports, so other teams want to hire their people. In 2014, Popovich hired the first female full-time assistant in NBA history. What do the Spurs want in a job candidate? Here was Popovich’s full response:

“Oh, boy. This is going to be a long interview (with reporters). For us, it’s easy. You’re looking for character,” he said. “Well, what the hell does that mean? We’re looking for people — and I’ve said it many times — who have gotten over themselves. You can tell that pretty quick. You can talk to someone for four or five minutes, and you can tell if it’s about them, or if they understand they’re just a piece of the puzzle. We look for that.

Assessing current fatigue of athletes to fine-tune training prescriptions is a critical task in competitive sports. Blood-borne surrogate markers are widely used despite the scarcity of validation trials with representative subjects and interventions. Moreover, differences between training modes and disciplines (e.g. due to differences in eccentric force production or calorie turnover) have rarely been studied within a consistent design. Therefore, we investigated blood-borne fatigue markers during and after discipline-specific simulated training camps. A comprehensive panel of blood-born indicators was measured in 73 competitive athletes (28 cyclists, 22 team sports, 23 strength) at 3 time-points: after a run-in resting phase (d 1), after a 6-day induction of fatigue (d 8) and following a subsequent 2-day recovery period (d 11). Venous blood samples were collected between 8 and 10 a.m. Courses of blood-borne indicators are considered as fatigue dependent if a significant deviation from baseline is present at day 8 (?fatigue) which significantly regresses towards baseline until day 11 (?recovery). With cycling, a fatigue dependent course was observed for creatine kinase (CK; ?fatigue 54±84 U/l; ?recovery -60±83 U/l), urea (?fatigue 11±9 mg/dl; ?recovery -10±10 mg/dl), free testosterone (?fatigue -1.3±2.1 pg/ml; ?recovery 0.8±1.5 pg/ml) and insulin linke growth factor 1 (IGF-1; ?fatigue -56±28 ng/ml; ?recovery 53±29 ng/ml). For urea and IGF-1 95% confidence intervals for days 1 and 11 did not overlap with day 8. With strength and high-intensity interval training, respectively, fatigue-dependent courses and separated 95% confidence intervals were present for CK (strength: ?fatigue 582±649 U/l; ?recovery -618±419 U/l; HIIT: ?fatigue 863±952 U/l; ?recovery -741±842 U/l) only. These results indicate that, within a comprehensive panel of blood-borne markers, changes in fatigue are most accurately reflected by urea and IGF-1 for cycling and by CK for strength training and team sport players.

BACKGROUND:

Autonomic regulation of heart rate (HR) as an indicator of the body’s ability to adapt to an exercise stimulus has been evaluated in many studies through HR variability (HRV) and post-exercise HR recovery (HRR). Recently, HR acceleration has also been investigated.
OBJECTIVE:

The aim of this systematic literature review and meta-analysis was to evaluate the effect of negative adaptations to endurance training (i.e., a period of overreaching leading to attenuated performance) and positive adaptations (i.e., training leading to improved performance) on autonomic HR regulation in endurance-trained athletes.
METHODS:

We searched Ovid MEDLINE, Embase, CINAHL, SPORTDiscus, PubMed, and Academic Search Premier databases from inception until April 2015. Included articles examined the effects of endurance training leading to increased or decreased exercise performance on four measures of autonomic HR regulation: resting and post-exercise HRV [vagal-related indices of the root-mean-square difference of successive normal R-R intervals (RMSSD), high frequency power (HFP) and the standard deviation of instantaneous beat-to-beat R-R interval variability (SD1) only], and post-exercise HRR and HR acceleration.
RESULTS:

Of the 5377 records retrieved, 27 studies were included in the systematic review and 24 studies were included in the meta-analysis. Studies inducing increases in performance showed small increases in resting RMSSD [standardised mean difference (SMD) = 0.58; P < 0.001], HFP (SMD = 0.55; P < 0.001) and SD1 (SMD = 0.23; P = 0.16), and moderate increases in post-exercise RMSSD (SMD = 0.60; P < 0.001), HFP (SMD = 0.90; P < 0.04), SD1 (SMD = 1.20; P = 0.04), and post-exercise HRR (SMD = 0.63; P = 0.002). A large increase in HR acceleration (SMD = 1.34) was found in the single study assessing this parameter. Studies inducing decreases in performance showed a small increase in resting RMSSD (SMD = 0.26; P = 0.01), but trivial changes in resting HFP (SMD = 0.04; P = 0.77) and SD1 (SMD = 0.04; P = 0.82). Post-exercise RMSSD (SMD = 0.64; P = 0.04) and HFP (SMD = 0.49; P = 0.18) were increased, as was HRR (SMD = 0.46; P < 0.001), while HR acceleration was decreased (SMD = -0.48; P < 0.001).
CONCLUSIONS:

Increases in vagal-related indices of resting and post-exercise HRV, post-exercise HRR, and HR acceleration are evident when positive adaptation to training has occurred, allowing for increases in performance. However, increases in post-exercise HRV and HRR also occur in response to overreaching, demonstrating that additional measures of training tolerance may be required to determine whether training-induced changes in these parameters are related to positive or negative adaptations. Resting HRV is largely unaffected by overreaching, although this may be the result of methodological issues that warrant further investigation. HR acceleration appears to decrease in response to overreaching training, and thus may be a potential indicator of training-induced fatigue.

PURPOSE:

The present study examined whether a period of additional speed endurance training would improve intense intermittent exercise performance in highly trained soccer players during the season and whether the training changed aerobic metabolism and the level of oxidative enzymes in type I and II muscle fibers.
METHODS:

During the last nine weeks of the season, thirteen semi-professional soccer players performed additional speed endurance training sessions consisting of 2-3 sets of 8 – 10 repetitions of 30 m sprints with 10 s of passive recovery (SET). Before and after SET, subjects completed a double-step exercise protocol that included transitions from standing to moderate-intensity running (?75% of maximal heart rate (HRmax)) followed by transitions from moderate to high-intensity running (?90% HRmax) in which pulmonary oxygen uptake (V?O2) was determined. In addition, the Yo-Yo Intermittent Recovery Test level 1 (YYIRT-1) was performed and a muscle biopsy was obtained at rest.
RESULTS:

YYIRT-1 performance was 11.6±6.4% (mean±SD) better (2803±330 vs. 3127±383 m, P<0.05) after compared to before SET. In the transition from standing to moderate-intensity running, phase II pulmonary V?O2 kinetics was 11.4±16.5% faster (P<0.05) and running economy at this intensity was 2.3±3.0% better (P<0.05). These improvements were apparent despite the content of muscle proteins regulating oxidative metabolism (HAD, COX IV and OXPHOS) and capillarization were reduced (P<0.05). The content of HAD and CS in type I and II fibers did not change.
CONCLUSION:

In highly trained soccer players, additional speed endurance training is associated with an improved ability to perform repeated high-intensity work. To what extent the training-induced changes in V?O2 kinetics and mechanical efficiency in type I fibers caused the improvement in performance warrants further investigation.

Is this the end of the NFL combine as we know it?

National Football Scouting Inc., which runs the combine, is establishing a committee of league executives, scouts, coaches, athletic trainers, team physicians and others to review all phases of the annual event starting this week in Indianapolis, according to company president Jeff Foster.

The NFL’s operations department also is involved in the review process, which will include periodic checkpoints through April’s draft and beyond, Foster said – a sign of increased interest at the league level in a possible overhaul amidst evolving technology and sports science.

… Over decades of coaching and consulting to thousands of executives in a variety of industries, however, my colleagues and I have come across people who succeed at this kind of learning. We’ve identified four attributes they have in spades: aspiration, self-awareness, curiosity, and vulnerability. They truly want to understand and master new skills; they see themselves very clearly; they constantly think of and ask good questions; and they tolerate their own mistakes as they move up the learning curve.

By now, you might have discovered that taming your sweet tooth as a New Year’s resolution is harder than you think.

New research by Duke University scientists suggests that a habit leaves a lasting mark on specific circuits in the brain, priming us to feed our cravings.

The aim of this study was to investigate the effects of 22 weeks of periodized training, with an emphasis on technical-tactical ability, on indirect markers of muscle damage and the on-field performance of young soccer players. Fifteen players (age 15.4 ± 0.2 years, height 172.8 ± 3.6 cm; body mass 61.9 ± 2.9 kg; % fat 11.7 ± 1.6; VO2max 48.67 ± 3.24 ml.kg.min) underwent four stages of evaluation: pre-preparatory stage – T0; post-preparatory stage – T1; post-competitive stage I – T2 and; post-competitive stage II – T3. The plasmatic activity of creatine kinase (CK) and lactate dehydrogenase (LDH) were evaluated as well as the on-field performance (movement patterns, tactical variables). Regarding the plasmatic activity of CK and LDH, there was a significant reduction (p ? 0.05) throughout the periodization training (T0: ~ 350 U/L; T3: ~ 150 U/L). Significant increases were observed (p ? 0.05) in the intensity of the game, high intensity activities (T0: ~ 22 %; T3: ~ 27%), maximum speed (T0: ~ 30 km.h; T3: ~ 34 km.h) and tactical performance, team surface area (T0: ~ 515 m; T3: ~ 683 m) and spread (T0: ~ 130 m; T3: ~ 148 m). In addition, we found significant inverse correlations between the percentage variation of T0 to T3 in CK and LDH activities with percentage variation in high intensity running (r = -0.85; p < 0.05 and r = -0.84; p < 0.01 respectively) and high intensity activities (r = -0.71 and r = -0.70; p < 0.05 respectively) during the matches. We concluded that there was reduced activity in biochemical markers related to muscle damage, as well as increases in-game high-intensity performance and the tactical performance of the study participants. Furthermore, players who showed greater reduction in plasma activity of CK and LDH also obtained greater increases in-game high-intensity performance along the periodization. These results may contribute to the expansion and future consolidation of the knowledge of coaches and sport scientists to develop effective methodologies for training in soccer.

Cluster of Excellence CITEC is developing a system to support athletes and patients in physical rehabilitation

A new system in a virtual training room is helping users practice and improve sports exercises and other motor activities: six research groups from the Cluster of Excellence Cognitive Interaction Technology (CITEC) at Bielefeld University are working on the ICSPACE project to develop this virtual coaching space. CITEC is funding this large-scale research project with 1.6 million Euro and it will run until 2017. During a project presentation the researchers showcased what their system is capable of. Using the example of a squat exercise, they presented the new technology, which will help not only athletes, but also physical rehabilitation patients learn movement exercises and correct their mistakes. In a new “research_TV” report from Bielefeld University, the coordinators of the project also explain how their new system works.

Background: A recent study found that an earlier age of first exposure (AFE) to tackle football was associated with long-term neurocognitive impairment in retired National Football League (NFL) players.

Purpose: To assess the association between years of exposure to pre–high school football (PreYOE) and neuroradiological, neurological, and neuropsychological outcome measures in a different sample of retired NFL players.

Study Design: Cross-sectional study; Level of evidence, 3.

Methods: Forty-five former NFL players were included in this study. All participants prospectively completed extensive history taking, a neurological examination, brain magnetic resonance imaging, and a comprehensive battery of neuropsychological tests. To measure the associations between PreYOE and these outcome measures, multiple regression models were utilized while controlling for several covariates.

Results: After applying a Bonferroni correction for multiple comparisons, none of the neurological, neuroradiological, or neuropsychological outcome measures yielded a significant relationship with PreYOE. A second Bonferroni-corrected analysis of a subset of these athletes with self-reported learning disability yielded no significant relationships on paper-and-pencil neurocognitive tests but did result in a significant association between learning disability and computerized indices of visual motor speed and reaction time.

Conclusion: The current study failed to replicate the results of a prior study, which concluded that an earlier AFE to tackle football might result in long-term neurocognitive deficits. In 45 retired NFL athletes, there were no associations between PreYOE and neuroradiological, neurological, and neuropsychological outcome measures.

Knee injuries are among the top five reasons people visit an orthopedic surgeon for treatments, which include 719,000 total knee replacements performed annually in the United States. Now, new research reveals underlying biomechanics that may be involved in meniscus fibrocartilage function as well as dysfunction and could guide novel treatments for some of the most debilitating and costly orthopedic problems in the U.S., including meniscus tears and age-related joint degeneration.

The knee meniscus is a piece of cartilage between the leg bones that cushions and stabilizes the joint, protecting the bones from wear and tear. In studies of samples from cows and humans, bioengineers funded by the National Institute of Biomedical Imaging and Bioengineering identified small patches of non-fibrous “islands” known as microdomains in the knee fibrocartilage that makes up the meniscus. Samples from older animals and humans consistently had larger microdomains. The discovery opens the way for a more detailed examination of fibrocartilage microstructure and how changes at the cellular and molecular levels contribute to orthopedic health and disease.

… I’m often asked “What’s the relevance of this particular drill, or why even bother with that?” My take as a former NFL decision maker is that a standard across an extended period of time allows for the ability to compare and contrast one draft class to another, one year’s position group with another, or one particular player with another. By and large the process and the drills haven’t changed much over time, though an entire cottage industry has sprung out of preparations for it. And certainly the Combine has become “must see” TV in the offseason for the rabid followers of the NFL.

So what matters most to me?

I lean towards a better understanding of the predictability of the skill drills as they relate to the past performance of other players who’ve succeeded in the NFL. That’s what the draft is all about; attempting to predict which players, based upon college productivity and a given data set of information, will most likely succeed at the next level.

So I thought an interesting project to finish the season on would be using analytics to select the England squad for Euro 2016. A few reasons for this – firstly the nonsense in the media about Rooney’s injury being bad for United and good for England.