Must Reads…and Some Classics

Here’s a list of five accessible articles we thought are a good start, must read, and of course are classics within the Biomechanics and Motor Learning literature. Throughout the year, we’ll continue to share articles grouped within themes that are applicable to all.

 

Motor Learning

  1. A Schema Theory of Discrete Motor Skill Learning
  2. Motor Skill Acquisition – K.M. Newell
  3. The Theory of Affordances
  4. A REVIEW OF THE CONTEXTUAL INTERFERENCE EFFECT IN MOTOR SKILL ACQUISITION
  5. Optimizing performance through intrinsic motivation and attention for learning: The OPTIMAL theory of motor learning

Biomechanics

  1. Kinematics vs. Kinetics 
  2. Inverse Dynamics
  3. THE PITFALLS OF 2D “BIOMECHANICAL” ANALYSIS
  4. A Guide for Coaches Looking to Invest in Force Plates
  5. Blog » Building Lateral Strength to Correct Crossover Gait Building Lateral Strength to Correct Crossover Gait

 

If you’d like to write for our blog, please feel free to reach out to either Jason or Harjiv.

 

The pen is the most powerful weapon in the world.

When we started the Rebel Movement, we wanted to use it as an avenue to write, share, dialogue, and most importantly, engage the world around us through a different form of media. In fact, we also saw it as a way to make mistakes. The fact is that we all have opinions, ideas, and thoughts, but struggle to find the medium to share such expressions within a post that is barred by character limitations.

This is an open call to anyone interested in writing. Please get in touch! Let’s truly harness the interdisciplinary nature of this art.

Here are some blog posts we have written for other great platforms.

Jason Avedesian 

Perform-X Training Systems – The Jump X

Harjiv Singh

Just Fly Sports- “Reorganizing the Athlete’s Brain”

Science for Sport – “Skill Acquisition”

 

 

Different but the Same: Enhanced Expectancy for Optimal Motor Performance

General Idea: Is there an underlying commonality between all theoretical approaches?

Opinion Piece : Harjiv Singh

There seems to be a clear divide amongst different theoretical and practical approaches to motor learning and performance. The field of motor behavior itself has become extremely interesting in the past few years. Information processing theorists have transitioned from task oriented approaches to more global motor learning theories whereas those from ecological psychology perspective have transitioned from affordances being opportunities for action to affordances being opportunities during action under a set of conditions or constraints. Both perspectives would agree that perception is believed to scale the world to reflect one’s own capabilities for action. Nonetheless, enhancing motor learning and performance is still dominated and rooted by practice conditions that make problem solving or information processing more difficult and effortful. While we remain stuck linearizing a non-linear central nervous system, the concern now shifts to not “what” but “how” to bring about coordinated or skilled control of complex movement, where movement execution is of primary concern. It’s not a coincidence that motivation, movement, and motor all share the same Latin root (movere, to move). The only way we learn new skills, adapt to differing constraints, and ultimately improve performance is through this idea of expectations, where we actively anticipate rewarding properties of significance to fulfill organismic needs and desires. Think about it, our situational specific confidence allows us to take advantage of hitting high hands even after we just completely shanked the ball (volleyball example). It is common knowledge that lack of confidence disrupts fluidity, but it’s also true that circumstances which enhance expectations may also potentate even more success, improvement, and learning. In fact, confidence has been recognized as a predictor of performance. Whether you follow an information processing or ecological psychology perspective, the common language we share is this idea of forward directed anticipatory cognitions about what is to occur which not only decreases self-focus but facilitates self efficacy and goal oriented motor performance. Recent work has shed light on autonomy supportive coaching, but we’re still light years behind engaging in such an idea. While both autonomy support and enhanced expectancy fall under the category of motivation, I think it is true that enhanced expectancy incorporates this idea of autonomy support. Thus, the question here is how can we enhance expectancies in practice and during competition? 

I try to keep it nice and short and too the point. I’m always willing to discuss further and dig deeper into the philosophy and science, just shoot me an email harjiv.singh@unlv.edu

   Screen Shot 2019-02-17 at 9.15.47 PM

  (Adapted from Wulf and Lewthwaite, 2016)

Pictured above is a pseudo motivational model that I will dig into through a psycholinguistic lens.  There have been numerous excellent motivational models for coaches in the past, but almost all view it through a practice condition lens. As much as we’re concerned with skill acquisition and practice conditions, words are more powerful and meaningful. Think about it, when your coach tells you something along the lines of, “I know you can do it” there is a sense of control that you assume because you’re no longer worried about pleasing your coach in the moment. Now, this may be the farthest we’ve gone in terms of enhancing expectancies. There is more to it and I hope to dig deeper into it below. For reference purposes, Psycholinguistics is the psychology of language. It is the study concerned with psychological and neurobiological factors that enable humans to acquire, use, comprehend, and produce language.

The bottom line here is that along with the typical organismic, task, and environmental constraints within the dynamical systems perspective, comprehension of language also serves as a constraint. Despite the ideology you follow, affordances are solutions of confidence and general motor programs are strategic constraints based on linguistic perceptions. 

Positive Feedback

An under appreciated function of feedback is its influence on an athlete’s motivational state. The research has clearly indicated that we want feedback on what we did good, not bad. Now, not saying if an athlete asks you for feedback on what they’re doing wrong you don’t give it. This very well maybe a way for the individual to enhance their own expectations. The feedback you do give though should be externally directed because it allows the athlete to focus primarily on the task goal. There are motivational characteristics to feedback. Reason being, an external focus primes the motor system to focus on the task goal, making it a performance criterion to accomplish that is attainable. At the same time, feedback should be instructional. When we start talking, it’s crucial to understand that our athlete will be thinking about what they did right, so a “nice job” vs. “nice job, I loved the way you flew like superman after that set” allows them to again, prime the motor system. You may be thinking that there are times where this external focus related feedback may not work especially during the cognitive stages of skill learning. After you’ve exhausted the distance effect (proximal and distal EF), it’s totally ok to go internal here, but the usage of action verbs is another way to offset the effects of the constrained action hypothesis. Research has clearly shown that the motor system is recruited during verb perception in the developing brain. The only caveat here is that your athlete needs to know what the verb actually means. So instead of telling your setter to “transfer the weight from your back foot to your front” you can easily say “push the ball towards the (target).” So clearly, theres more to positive feedback. 

Conception of ability

An athlete’s view of their own ability as reflected by a fixed capacity versus being amenable to change with practice can affect their motivation but also influence their performance and learning. Conception of ability is a directly correlated to the influence of task instructions or performance feedback. When we give feedback and say “you’re an excellent server” vs saying “those serves were very good” you’re telling your athlete that what he/she just did was good (working memory) and that what was good, were the serves. Now, the athlete can go back and monitor what happened during those serves, why where they so good? what did I feel? what did I do differently? etc. Let’s put it into context. If as a coach I tell you prior to a serve that you are a great server, there maybe a sense of nervousness which has been shown in the literature. This is also combined with a more internal focus because now if you miss, its no longer an amenable skill but a fixed capacity. 

Positive Affect

Practice should accompany positive affect. Anticipation of positive affect is a form of enhanced expectancy. But outside representative design, positive affect can be influenced by what we say. Research has documented numerous times that with positive affect, there seems to be a sense of cognitive flexibility and creativity. It’s this conviction that one is doing well and the confidence in being able to perform well in the future that drives the “wanting” of rewards. Going back to the two predominant theoretical approaches, an affordance may just be a sense of confidence. We have all these opportunities for action yet we chose what we chose. However, the instruction or feedback evidently guides this. If as a coach, my athlete accomplishes the task goal differently then I wanted, my negative feedback towards him/her negates and positive affect. And the research seems pretty convincible that for instance, an external focus allows for more goal directed behavior as measured through the UCM approach. But, even then, to create this positive affect, you need to buy into an autonomy supportive style of coaching. Avoid the “you have to” “I need you to” “do this” “be quicker” etc. Stop demanding your player and start suggesting. Simple words like “can you” “let’s try” “how about” or articles such as “the” instead of “my” can elicit less controlling behaviors and less self focus. 

Self Modeling

Self modeling is great because almost all coaches do it. There are several ways to this including editing videos of your athletes best performances which by the way are also subjective. Nonetheless, another way is to actually self model in real time. However, again, coaches fall into this rut of talking too much and giving very self focused cues. The cues you give during self modeling need to be similar to those you give when instructing/providing feedback. There needs to be direction, description, and even distance. The idea here is to increase intrinsic motivation. Most teams nowadays use a video playback system but again when analyzing, they give vastly different cues than they do during the acquisition and performance phase. Also, providing too much “feedback” via self modeling is not good. What I want to stress mostly is that the verbiage 

should be defined and similar across all tasks. 

Perceived Task Difficulty

Setting criteria that purportedly indicate good performance but can also be reached easily can also raise expectancies. You want to challenge your outside hitter to hit more line? great, what are the smaller victories in between? perhaps, a tip down the line by the ten foot line. Using a point system can also guide this effect where you don’t constrain your server to hit the gap between 5/6, but add more passers so that they have to figure it out within the provided solution space. This gives them autonomy. Lastly, providing them choices is probably the most easiest to do during practice. The word “or” goes a long way. Provide them with choices that they feel confident in, after all, its their affordance, not yours. For example, “drive the ball to the end line, or push it to the right side of the court.” When you challenge, make sure it’s attainable, in which case the environment matters. 

To conclude, expectancies affect attention and cognition. It influences working memory, long term memory, all biased towards expected stimuli. By doing so, athletes pay more attention to task error cues, increase reaction times, and increase pre-movement excitation, to name just a few. My intention here was to give you a little insight on the possibility that all of these theoretical approaches may just be underlined by this concept of enhanced expectancy and that there is more to practice conditions. It still intrigues me that words affect how we move, and words have an emotional component to them which affects confidence or expectancy. As coaches and clinicians, we need to go beyond simple motor programs. As an introduction my own research efforts, I hope to eventually take this and study the motivational characteristics of language as it related to motor learning and performance.

Five Thoughts on Sprint Technique – Ryan Banta

Part 1 of building a sprint culture by Ryan Banta, girl’s head track & field coach at Parkway Central High School. Ryan has coached multiple state champions, national qualifiers, and collegiate track & field athletes.

What are Ryan’s thoughts on sprint technique? In this video, Ryan discusses:

  • Why teaching sprint technique works
  • #BeTheHashtag
  • How often should you train sprint mechanics?
  • Individual technique
  • Injury reduction and sprint technique

https://www.youtube.com/watch?v=9kEa6NqEYAg&feature=youtu.be

Sport-Related Concussion and Lower Extremity Injury

Sport-Related Concussion and Lower Extremity Injury

In this blog, I will be discussing the primary research I am conducting for my PhD studies at the University of Nevada, Las Vegas.  It has been a bit since I last posted, so I figured it would be best to provide an update of what I have been doing all semester, so I hope you enjoy!  (One caveat, I’m not going to reference any literature in this piece, this will be based strictly off my knowledge of the current research.  I recently submitted a literature review on this topic for peer-review with the expectation of publication in the near future.  I will certainly share this heavily referenced text once that process is complete).  Before I get into the nitty gritty of this post, I’d like to start with a cliff notes version of the crux of my dissertation research, which will be followed by a more in-depth analysis.

Sport-related concussions (SRCs) are now classified as a major public health crisis affecting athletes across all major sporting levels.  Injury surveillance data has recently determined that compared to their non-concussed counterparts, athletes who sustain a SRC are at greater risk for lower extremity injury well beyond the resolution of traditional SRC assessment batteries.  This may in part be attributed to subtle cognitive and neuromuscular deficits that are exposed during dynamic sporting tasks.  However, the current literature has yet to elucidate the biomechanical movement patterns of sport-specific activities (i.e. jump-landing) post-SRC.  Examination of lower extremity biomechanics after a concussive event may offer objective analysis to provide a rationale for the association between SRC and lower extremity injury risk.  Therefore, the purpose of my research is to examine jump-landing biomechanics in adolescent and collegiate athletes with and without a history of SRC.

Our knowledge of SRCs have come a long way in the past few decades.  Initially viewed as a lack of “mental toughness”, we are now starting to understand the short- and long-term ramifications of this injury.  Millions of athletes per year will sustain a SRC across all sporting levels.  While (US) football receives most of the media attention, sports such as soccer, ice hockey, and lacrosse also pose significant risk for a concussive injury.  While the risk of subsequent SRCs are significantly (up to 6x) higher following a first concussive event, what many do not know is that these same athletes are at a much greater risk for a lower extremity injury (i.e., anterior cruciate ligament (ACL) tears, ankle sprains, hamstring strains, etc.) for reasons that are largely unknown at this point.  Specially, concussed athletes across sporting levels (high school, collegiate, and professional) are at an approximately 1.5 – 4 times greater risk for the aforementioned injuries when compared to athletes who have not sustained a SRC.  But here’s where it gets really interesting: The risk of lower extremity injuries post-SRC extends well beyond the resolution of traditional SRC reporting measures – in some cases up to a year after the initial concussive event.  In order to best understand the SRC complexity, practitioners must first understand the common assessment batteries administered following such an event.  Following this, I discuss why these measures may lack the precision to adequately detect an at-risk athlete for further injury, particularly to the lower extremity.

The three most common ways to assess a SRC are as follows: symptom reporting, neurocognitive evaluation, and balance / sway measures.  However, there are issues with all three in terms of returning an athlete back to the field.  Bearing in mind that I value all of these tools as part of a multifactorial approach to SRC assessment, it is my goal to develop methods in conjunction with these tools to mitigate further injury after a SRC. Let’s discuss.

Symptom Reporting: With symptom reporting, many athletes (especially adolescents) are unaware of the most common signs following a sustained SRC.  There have been numerous studies published on the lack of SRC knowledge at the youth level and it continues to be a big problem (If interested, I can provide a few posters from the CDC HEADS UP program to share with your team!).  Another issue is that some athletes will attempt to hide their symptoms in order to stay on the field, there’s a reason why approximately 50% of all SRC are believed to go unreported.  This is typically the case in male contact sports, as the literature indicates that female athletes are much more likely to report a suspected SRC.  What we must understand is that not every SRC is obvious.  Some athletes will experience a headache that can be easily passed off as just the nature of contact sports.  Others will demonstrate obvious signs such as postural imbalances, dizziness, or loss of consciousness.  The main takeaway with symptom reporting is that education for athletes, parents, and coaches is an absolute must at the start of every season.  Even more important is re-education throughout the year, which can be as simple as impromptu quizzes at the end of a training session.

Neurocognitive Evaluation: Neurocognitive exams can be administered with a paper-and-pencil or computerized testing module.  These test batteries evaluate various neurocognitive performance indices such as verbal memory, visual memory, reaction time, and visual motor processing speed, and impulse control.  While neurocognitive testing has demonstrated superior sensitivity and specificity for determination of a sustained SRC, there a few limitations that must be considered.  First, there are issues with athletes “sandbagging” the baseline exam, especially those at the collegiate and professional levels.  These athletes are aware of the ramifications of their baseline score, a poor score at the start makes it that much easier to surpass if a SRC were to occur mid-season.  This limitation is more directed toward the paper-and-pencil exams, as the computerized modules are typically equipped with validity benchmarks.  When an athlete is subjected to neurocognitive testing post-SRC, they are often administered multiple (3-5) exams within a very short time period, potentially inducing practice effects.  Essentially what this means is that athletes may score higher on these exams just because they are more familiar with the test itself and may learn testing strategies to score higher.  When these exams are administered to non-concussed control athletes over the same time period, baseline scores are typically surpassed.  Therefore the question becomes, should concussed athletes be required to best their baseline scores in order to be cleared to play?

The last thing I want to discuss is the administration of these neurocognitive exams.  Athletes are seated in a quiet room alone to minimize any distractions – almost the exact opposite of their dynamic sporting environment.  This situation begs the question of the generalizability of the results given the conditions.  During training and competition, athletes are required to interpret task relevant (e.g., opposition and teammate position) and irrelevant (e.g., crowd noise) environmental cues while performing complex motor tasks.  Further, these tests do not account for mental or physical fatigue.  An athlete may perform to “baseline” during a computerized exam, but do they demonstrate this same performance in the 4th quarter?

Balance / Sway Measures: The two most common balance and sway measures post-SRC are the Balance Error Scoring System (BESS) and Sensory Organization Test (SOT).

                                      BESS                                               SOT

The BESS test is subjectively scored by the clinician as the athlete completes various stances on two surface conditions (flat and foam) with their eyes closed.  Error scores are calculated (e.g., opening eyes, lifting hand off hip) for each stance condition over the course of 20 second trials. Despite athletes typically requiring a greater recovery time, BESS data has demonstrated impaired postural control up to 3-5 days post-SRC.  However, recent review papers on the BESS has demonstrated inadequate reliability in a clinical setting (< 0.75), and this may be attributed to the subjective nature of the test (e.g., different clinicians analyzing the same athlete over an acute time frame) and the aforementioned practice effects from repeated testing.

On the other hand, the SOT produces objective balance scores utilizing dynamic posturography under six different stance conditions.  Sensory deprivations under certain conditions allow the SOT to determine visual, vestibular and / or proprioceptive impairments.  Not surprisingly, the SOT has demonstrated superior sensitivity and reliability, when compared to the BESS.  Reviews of SOT data have demonstrated balance impairments up to 10 days following a SRC.  However, researchers question the practicality of the SOT, again due to its analysis of static posture not representative of dynamic sporting movements.  Additionally, the SOT is a very expensive tool, excluding many concussed athletes from access to this type of analysis.

So you have stated the issues…what are the solutions?

To reiterate, I believe the above-mentioned assessment tools have great clinical utility and should absolutely be implemented prior to- and post-SRC.  My concern lies in the ability of these tools to translate into a dynamic sporting environment that poses a potentially  heightened risk for a lower body injury post-SRC.  However, recent gait analysis in concussed athletes has demonstrated locomotor deficits that extend beyond the resolution traditional SRC management tools.  Post-SRC, adolescent and collegiate athletes have demonstrated slower walking speeds, greater frontal plane instability, and decreased cognitive performance as the gait task becomes increasingly difficult (e.g., performing a dual motor and/or cognitive task).  Studies have also obstacle avoidance strategies during gait that suggest deficiencies in executive functioning, spatial awareness, and information processing.  It is recommended that gait analysis be included within a SRC assessment protocol, but more research is warranted to determine best practices in sport.  Perhaps it is best to have the athlete perform various walking tasks (i.e., forward, backward, and tandem) while implementing a cognitive task (i.e., reciting the months backwards or counting by threes).

oldham_2017

(Oldham, 2017)

This now brings me to my current research.  Specifically, I am examining jump-landing biomechanics in adolescent and collegiate athletes with and without a history of SRC.  My (current) first study is in the adolescent population.  Thus far, our data has shown landing mechanics that would suggest a greater risk of injury to the lower body in those who have sustained a previous SRC.  Post-SRC, athletes are demonstrating greater ground reaction forces and loading rates, increased knee valgus angles, and less sagittal knee ROM during various landing tasks.  A large sample size is necessary before making any definitive conclusions, but if these patterns hold with a larger n, it may start to provide a biomechanical explanation as to why athletes are at greater risk for a lower body injury post-SRC.  It has been suggested that subtle cognitive and neuromuscular impairments linger well after an athlete has been cleared for sporting participation.  Biomechanical analysis of dynamic, complex movement tasks may help reveal these abnormalities that are not detected by our traditional reporting measures.  The goal moving forward with these studies is to incorporate cognitive stressors during the jump-landing maneuvers to make the analysis more sport-specific.  With the tools and the assistance of my current research, it is the hope that we will be able to further advance and develop appropriate lower body movement screenings that will be quintessential to any SRC toolbox. Stay tuned!

(Adolescent landing biomechanics from my first concussion study)

Thanks for reading!

Jason

Twitter: @JasonAvedesian

Email: jason.avedesian@unlv.edu

 

#BernsteinBuzz – September 2018

220px-Cyclogram_Gastev_TSIT

Topic: How to mitigate cognitive noise?

 

The #BernsteinBuzz, an interdisciplinary effort to studying skill acquisition, is a monthly conference call series started by Harjiv in May 2018. With participants spanning all backgrounds, we bring together those in coaching, research, biomechanics, neuroscience, rehabilitation, and psychology, just to name a few. In memory of Nikolai Bernstein, a Russian neurophysiologist and pioneer in motor control and learning, our aim is to use each other’s strengths to build each other’s weaknesses and provide our industry with a new perspective of philosophy and science. These calls are open to anyone, please reach out to Harjiv at singh.harjiv@gmail.com.

Using this platform, we will share each call’s recordings. Thanks!