Applied Sports Science newsletter – July 18, 2016

Every morning, members of the Chicago Cubs eagerly check their phones. What awaits them is a text message with the answer to a pressing question: What position are they playing that day?

For any other team, this cliffhanger would be as suspenseful as discovering the soup of the day in the clubhouse kitchen. Most players show up to the ballpark, glance at the lineup card and find that they’re playing in the exact same spot they usually do.

But Cubs players report for duty every day with no earthly idea where they will be stationed in the field. “If you’re moving all over the place, there’s some mystery to it,” said Kris Bryant, the Cubs’ third baseman/left fielder/right fielder/first baseman/center fielder/shortstop.

Introduction: In previous work, acute high-intensity aerobic exercise benefited continuous motor sequence task learning. As memory processes underlying motor sequence learning vary between tasks involving continuous and discrete movements, the objective of the current study was to determine if the beneficial effects of acute aerobic exercise generalize to the learning of a discrete motor sequence task.

Methods: Sixteen young healthy individuals practiced a discrete motor sequence task preceded by either a period of rest or a bout of high-intensity cycling. Participants moved a cursor with a computer mouse to a series of discretely-presented targets on a screen. Target presentation followed either a repeated or random sequence, which allowed evaluation of implicit sequence-specific motor learning. Change in movement response time over practice ([INCREMENT]-ACQ) and from practice to a 24-hour ‘no-exercise’ retention test ([INCREMENT]-RET), as well as rate of improvement over practice ([alpha]-ACQ) and during the retention test ([alpha]-RET) were calculated.

Results: [alpha]-RET was greater for the repeated sequence than random sequences following aerobic exercise (p = .01), but not rest (p = .33). Further, [alpha]-RET for the repeated sequence was greater following aerobic exercise than for either sequence (repeated, random) in the rest condition (p = .57).

Conclusion: Our findings show a positive effect of acute high-intensity aerobic exercise on implicit discrete motor sequence learning. Performing exercise prior to practice increased the rate of improvement at a 24-hour delayed retention test, suggesting an impact on the rate of motor memory retrieval. Pairing acute aerobic exercise with motor practice may facilitate learning of discrete movement sequences in sport or rehabilitation settings.

A model that takes into account the current workload, and the workload the athlete has been prepared for, as an acute:chronic workload ratio has been previously used as a novel way to monitor training load and injury risk. Fifty-nine elite Australian football players from one club participated in this 2-year study. Global Positioning System technology was used to provide information on running workloads of players. An injury was defined as any non-contact “time-loss” injury. One-week (acute), along with 4-week (chronic) workloads were calculated for a range of variables. The size of the acute workload in relation to the chronic workload was calculated as an acute:chronic workload ratio. An acute:chronic workload ratio of >2.0 for total distance during the in-season was associated with a 5 to 8-fold greater injury risk in the current [relative risk (RR) = 8.65, P = 0.001] and subsequent week (RR = 5.49, P = 0.016). Players with a high-speed distance acute:chronic workload ratio of >2.0 were 5–11 times more likely to sustain an injury in the current (RR = 11.62, P = 0.006) and subsequent week (RR = 5.10, P = 0.014). These findings demonstrate that sharp increases in running workload increase the likelihood of injury in both the week the workload is performed, and the subsequent week.

Injury aetiology models that have evolved over the previous two decades highlight a number of factors which contribute to the causal mechanisms for athletic injuries. These models highlight the pathway to injury, including (1) internal risk factors (eg, age, neuromuscular control) which predispose athletes to injury, (2) exposure to external risk factors (eg, playing surface, equipment), and finally (3) an inciting event, wherein biomechanical breakdown and injury occurs. The most recent aetiological model proposed in 2007 was the first to detail the dynamic nature of injury risk, whereby participation may or may not result in injury, and participation itself alters injury risk through adaptation. However, although training and competition workloads are strongly associated with injury, existing aetiology models neither include them nor provide an explanation for how workloads alter injury risk. Therefore, we propose an updated injury aetiology model which includes the effects of workloads. Within this model, internal risk factors are differentiated into modifiable and non-modifiable factors, and workloads contribute to injury in three ways: (1) exposure to external risk factors and potential inciting events, (2) fatigue, or negative physiological effects, and (3) fitness, or positive physiological adaptations. Exposure is determined solely by total load, while positive and negative adaptations are controlled both by total workloads, as well as changes in load (eg, the acute:chronic workload ratio). Finally, we describe how this model explains the load—injury relationships for total workloads, acute:chronic workload ratios and the training load—injury paradox.

Aidy Boothroyd turned up for his first day as an apprentice at Huddersfield Town carrying a pair of brand new boots. He was 16, eager to look the part and to make a good first impression. “I thought we’d do a bit of running, then get into training,” he says. “Instead, the manager just looked at me and said, ‘I don’t know what you think you’ll be doing with them.’ ”

In the late 1980s, when Boothroyd was coming through, learning to be a footballer did not involve fripperies such as practising football. As a YTS scholar, he spent his days “cleaning boots, cleaning the toilets, mopping the floors,” he says. “We would be running up and down the steps, cleaning these enormous, 60-foot stands. It was frightening. It was a tough environment, but it did you good.”

In the aftermath of England’s humiliation at Euro 2016, a strain of thinking has taken hold that, perhaps, a return to those days might not be such a bad thing. A chorus of former players, in particular, have suggested that life in the Premier League’s state-of-the-art academies has inadvertently turned English players, in the words of Jamie Carragher, “soft physically and soft mentally”.

… Between the U23’s loss to Colombia and the start of the Copa, ESPN FC asked some of the brightest minds in the domestic game, guys who are on the front lines, two simple questions: What’s the state of youth development in the U.S.? And how can it improve?

The 10 respondents are diverse in their backgrounds, having either played or coached (or both) in the U.S. and abroad. They definitely had no shortage of insight.

If you do an unusually hard workout – perhaps a run with lots of steep downhills and other unfamiliar movements – you’ll probably be sore the next day. How sore? That depends, you would think, on just how much damage you’ve done to your muscles.

But there may be more to it, according to an interesting study by Eric Hall and Nicole Razor of Elon University that was presented at the American College of Sports Medicine annual meeting last month. They used a series of psychological questionnaires to look at how attitudes toward pain affected perception of soreness following a high-intensity workout in 35 collegiate athletes.

The study explored the consequences of “fear-avoidance,” the idea that being overly concerned about avoiding pain after an injury can lead to a vicious cycle that prevents you from resuming normal activity, which delays healing and thus ensures that pain (and subsequent avoidance) continues. In other words, being worried about pain can be more debilitating than the pain itself.

… When I work with a client on a new skill (especially if they’re a new client I haven’t worked with before), I try to under-coach at the beginning and build up as we go. What I mean by this is I’ll start with an exercise and simply outline the starting position and the motion I want them to go through. I might include one or two concepts on top of that like how to breathe or where they should feel it working, but that’s about it.

From there, I watch how they perform the movement and see whether I need to step in to offer any other coaching cues to help them get closer to the desired effect of the exercise. This way I only have them focus on the stuff they need to focus on at the time and limit the unnecessary (at that time) confusion about the movement until they have a decent handle on it.

After the set I’ll ask a couple of key questions: what did you feel working? Did that feel easy or hard for you? Were you doing anything during that that helped you find some success with the movement?

Background: Rehabilitation before anterior cruciate ligament (ACL) reconstruction (ACLR) is effective at improving postoperative outcomes at least in the short term. Less is known about the effects of preoperative rehabilitation on functional outcomes and return-to-sport (RTS) rates 2 years after reconstruction.

Purpose/Hypothesis: The purpose of this study was to compare functional outcomes 2 years after ACLR in a cohort that underwent additional preoperative rehabilitation, including progressive strengthening and neuromuscular training after impairments were resolved, compared with a nonexperimental cohort. We hypothesized that the cohort treated with extended preoperative rehabilitation would have superior functional outcomes 2 years after ACLR.

Study Design: Cohort study; Level of evidence, 3.

Methods: This study compared outcomes after an ACL rupture in an international cohort (Delaware-Oslo ACL Cohort [DOC]) treated with extended preoperative rehabilitation, including neuromuscular training, to data from the Multicenter Orthopaedic Outcomes Network (MOON) cohort, which did not undergo extended preoperative rehabilitation. Inclusion and exclusion criteria from the DOC were applied to the MOON database to extract a homogeneous sample for comparison. Patients achieved knee impairment resolution before ACLR, and postoperative rehabilitation followed each cohort’s respective criterion-based protocol. Patients completed the International Knee Documentation Committee (IKDC) subjective knee form and Knee injury and Osteoarthritis Outcome Score (KOOS) at enrollment and again 2 years after ACLR. RTS rates were calculated for each cohort at 2 years.

Results: After adjusting for baseline IKDC and KOOS scores, the DOC patients showed significant and clinically meaningful differences in IKDC and KOOS scores 2 years after ACLR. There was a significantly higher (P < .001) percentage of DOC patients returning to preinjury sports (72%) compared with those in the MOON cohort (63%).

Conclusion: The cohort treated with additional preoperative rehabilitation consisting of progressive strengthening and neuromuscular training, followed by a criterion-based postoperative rehabilitation program, had greater functional outcomes and RTS rates 2 years after ACLR. Preoperative rehabilitation should be considered as an addition to the standard of care to maximize functional outcomes after ACLR.

Anterior cruciate ligament (ACL) tears are common knee injuries sustained by athletes during sports participation. A devastating complication of returning to sport following ACL reconstruction (ACLR) is a second ACL injury. Strong evidence now indicates that younger, more active athletes are at particularly high risk for a second ACL injury, and this risk is greatest within the first 2 years following ACLR. Nearly one-third of the younger cohort that resumes sports participation will sustain a second ACL injury within the first 2 years after ACLR. The evidence indicates that the risk of second injury may abate over this time period. The incidence rate of second injuries in the first year after ACLR is significantly greater than the rate in the second year. The lower relative risk in the second year may be related to athletes achieving baseline joint health and function well after the current expected timeline (6-12 months) to be released to unrestricted activity. This highlights a considerable debate in the return to sport decision process as to whether an athlete should wait until 2 years after ACLR to return to unrestricted sports activity. In this review, we present evidence in the literature that athletes achieve baseline joint health and function approximately 2 years after ACLR. We postulate that delay in returning to sports for nearly 2 years will significantly reduce the incidence of second ACL injuries.

PURPOSE:

To identify the impact of anterior cruciate ligament (ACL) reconstruction on performance and career longevity for National Basketball Association (NBA) players.
METHODS:

Seventy-nine players (80 knees) with acute ACL tears in the NBA between the 1984-2014 seasons, and 112 age, height, weight, and performance-matched controls were identified. Pre- and post-injury performance outcomes including seasons played, games played, games started, minutes per game, points per game, field goals, 3-point shots, rebounds, assists, steals, blocks, turnovers, personal fouls, usage percentage and player efficiency ratings were compared between cases and controls using independent samples t tests and Fisher’s exact tests.
RESULTS:

Sixty-eight of seventy-nine players (86.1 %) returned to play in the NBA following ACL reconstruction. Mean length of post-operative play was 1.84 years shorter than matched controls (P = 0.001). There was a significantly higher rate of attrition from professional basketball for players with a history of ACL reconstruction (P = 0.014). In the first full season following surgery, players started in 15.5 fewer games (P = 0.001), they played in 17.3 fewer games (P < 0.001), and had combined player efficiency ratings 2.35 points lower (P = 0.001) when compared to matched controls. Over the length of their careers, players competed in 22.2 fewer games per season (P = 0.009).
CONCLUSIONS:

There is a high rate of return to sport in the NBA following ACL reconstruction, although playing time, games played, player efficiency ratings and career lengths are significantly impacted in the post-operative period. These data should be used to manage patients’ expectations regarding their abilities to return to elite levels of athletic performance.

I just turned 40, and no matter how well I take care of myself, I’m going to be seeing doctors more often as I continue to age. First, there are the sundry screenings one starts to require in middle age, mammograms and colonoscopies and the like. Plus, the risk of common ills such as hypertension and high cholesterol (both of which run in my family) starts to inch up. But being a good patient can be hard, as I found out last year during an extended but—I realize now—fully preventable dental ordeal. Here’s what health and psychology studies have to say about becoming better partners in our own health.

I would like to recommend Revisionist History, a new podcast from Malcolm Gladwell. His third podcast, The Big Man Can’t Shoot, nominally covered Wilt Chamberlain and his struggles at the free throw line. But, as is often the case with Gladwell’s work, it’s about so much more than that.

Of particular interest to me was the academic paper Gladwell cited, which formed the meat of the podcast. It was written by Mark Granovetter, back in 1978, and is titled Threshold Models of Collective Behavior. Here’s a link to the paper, which I recommend reading if you have the time. But a couple of Granovetter’s examples resonated with me as being particularly relevant o us, and I would like to reproduce them here using a football analogy.

Recently, the statistical analyst of an NHL team was let go in the aftermath of an underwhelming regular season and a puzzling decision involving one of the team’s most productive and iconic players. Rights and wrongs aside, the episode illustrated an uncomfortable fact: the analyst’s job is perhaps the most fragile one of all.

Imagine the tightrope walker, balancing him/herself atop a fine metal wire between two buildings. The job is a difficult one on the best of days, requiring a lifetime of practice and undivided focus. Randomness is not the tightrope walker’s friend. A gust of wind, a slight mis-step or even a meeting with an errand low-flying pigeon could yield deadly consequences.

While the physical stakes are different, an analyst’s career prospects (and personal well-being) are similarly affected by things out of his or her control. While job security in any field is dependent on market conditions, things are especially dire for the technical worker responsible for uncovering Truths, but ranked too low in the corporate hierarchy to effect real change.

Just over three years to the day since Leonardo left his position as Paris Saint-Germain’s sporting director, the French champions have found somebody to fill the void left by the Brazilian transfer guru. In a surprise announcement on Thursday, the club revealed that Patrick Kluivert is the new director of football at the Parc des Princes.

The 40-year-old Dutchman’s arrival has not concerned fans in the capital but it does raise questions over the off-the-pitch direction in which the Ligue 1 giants are heading.