JEFF CUBOS
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Movement Patterns of the Lumbar Spine and Sacrum During the Back Squat

2/10/2011

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Study Title: The Lumbar and Sacrum Movement Pattern During the Back Squat Exercise
Authors: MR McKean, PK Dunn & BJ Burkett
Journal: Journal of Strength & Conditioning Research
Date: October 2010

Summary:
  • Here is a recent article that takes a deeper look at the obvious. McKean and colleagues utilized thirty upper year personal training students and personal trainers to examine 1) the timing and range of movement of the lumbar and sacral regions and 2) the influence of stance width, gender, and ascent / descent phases during the back squat exercise. Incorporating no load and 1.5 x body weight loaded trials, measurements from 3-D tracking devices placed on the above regions were evaluated for maximum lumbar and sacrum angles, the time at maximum lumbar and angles, maximum lumbar flexion angles, and the time at maximum lumbar flexion angles. Unsurprisingly, it was revealed that both men and women achieved a deeper squat position with wider stance (twice ASIS width) versus narrow stance (equal to ASIS width) positions. For those interested in the technical rationale, the reasoning behind this was lower maximum lumbar, sacrum and lumbar flexion angles leading to the ability to maintain more upright lumbar spine positions. Men and women, however, differed in movements and timing of maximums where men achieved maximum sacral angles sooner for both the ascent and descent phases of the squat in comparison with women who achieved earlier maximum lumbar angles in both phases. As a result, this modification in sacrum position and timing in men appears to allow them to accommodate for the known gender differences in pelvic girdle morphology. From a safety perspective, the above differences between the narrow and wider stance positions allow the lumbar spine to maintain a more upright position decreasing the load on the posterior structures of the spine.  That said, kyphosis of the lumbar spine does occur during the deep squat although measurements were not collected beyond ASIS width.

McKean MR et al. (2010). The lumbar and sacrum movement pattern during the back squat exercise. Journal of Strength and Conditioning Research, 24(10); 2731-2741
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Methods to Enhance Motor Skill Learning

2/7/2011

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This recent paper by Gabriele Wulf and colleagues investigated the potential factors involved in motor skill learning. Particularly focusing on the influence several variables may have on the learning and performance of specific motor skills as they pertain to the medical field, a review of the literature was performed. Fortunately, the following factors may be applied to a wide range of settings and be of use by those in education, rehabilitation, and sports performance...to name a few. It was suggested that learning can be particularly enhanced when the learner's motivation is optimized.

Learning: "a relatively permanent change in a person's ability to perform a skill"

OBSERVATIONAL LEARNING

  • In combination with physical practice, observational practice has been demonstrated to contribute highly to the acquisition of motor skills via mutual activation of the cerebellum, cingulate gyrus, inferior parietal lobe, premotor cortex, and supplementary motor area. The combination of such observational and physical practice is said to provide the opportunity to both extract important information pertaining to coordinated motor patterns as well as evaluate effective strategies that otherwise would be difficult if one were to both prepare and execute simultaneously. Therefore, observation provides the opportunity to "process". Additionally, alternating between observation and physical practice (performing a dyad) allows the learner to observe and apply. This facilitates enhanced motivation.

ATTENTION FOCUS
  • This variable pertains specifically to movement in relation to space and time. Ideally, attention should be directed to the induction of an external focus in contrast to one that is internal. Through simple changes in cues utilized, performance and learning can greatly be enhanced. For example, instructing a patient to "thrust his/her pelvis to the ceiling" will performing a glute bridge would be a more effective cue than suggesting he/she "activate the glutes and extend the hips". Similarly, greater gains will likely be witness in a training environment when asking a squatting athlete to "sit back onto a chair" as opposed to "flex your hips keep your tibia vertical". This external focus has been shown to facilitate automaticity of movement  and the use of unconscious processes, therefore reducing unwanted attentional demands.

FEEDBACK
  • Commonly pertaining to "knowledge of results" and "knowledge of performance", feedback has been demonstrated to highly influence motivation. Specifically when provided following "good" trials, feedback is said to facilitate more effective learning through positivity. Further, normative feedback, that is, feedback in relation to the performance of others (or the norm), enhances self-efficacy and motivation. This is true even in such instances when feedback was false (i.e. saying "great job" - even though performance was relatively poor). Therefore, rather than providing neutral information, positive feedback in specific situations will enhance self-fulfillment and motivation, thereby affecting learning.

PRACTICE THAT IS SELF-CONTROLLED
  • Providing the learner with the opportunity to control their practice conditions has been demonstrated to be an effective method for the learning of motor skills. Allowing the learner to dictate when or when they do not want to receive feedback seems to be of greater importance than frequency of feedback. Additionally, occasionally permitting the individual to decide when they choose to practice facilitates greater active involvement and subsequently, enhanced motivation, self-control and effort. Such practice and learning conditions may also pertain to free play (allowing the athlete to spend extra time in the weightroom, court, or ice) and recreational exercise (performing rehabilitation exercises at home or in the gym).

As you can see, there are no shortage of methods for us as rehabilitation and exercise professionals to become more effective "teachers". In utilizing some of the above principles in the strategies we employ, we may become more effective practitioners and facilitate better means of motor skill acquisition.

Reference: Wulf G, Shea C & Lewthwaite R. (2010). Motor skill learning and performance: a review of influential factors. Medical Education, 44; 75-84 
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Yoga for Persistent Pain

2/3/2011

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Study Title: Yoga for Persistent Pain: New Findings and Directions for an Ancient Practice
Authors: A Wren, M Wright, J Carson & F Keefe
Journal: Pain
Date: 2011

Summary:
  • Derived from the Sanskrit verb “yug” which means to bind or join, the term yoga has traditionally referred to the unification of the mind and body for the promotion of health. Commonly advocated for its potential effect on painful conditions and in light of our knowledge of pain as an entity that cannot exist without the presence of the brain, recent research has examined the role yoga may play in painful conditions. Recognizing its comprehensive two-way nature, appreciating this role seems less than difficult.
  • This paper reviewed 9 of 13 randomized control trials (RCTs) that examined the efficacy of yoga for persistent pain. Several of these existing studies have looked at its physiological, behavioural, and psychological effects on carpal tunnel syndrome, hand osteoarthritis, low back pain, fibromyalgia, and other chronic (including that associated with cancer) pain conditions. Significant reductions in pain, physical disability, depression, medication, fatigue, and sleep disturbance were found. Although certain outcome measures between experimental and control groups were also found insignificant, the therapeutic role of specific forms of this ancient practice management of persistent-painful conditions was no less than apparent.

Wren AA et al. (2011). Yoga for persistent pain: New findings and directions for an ancient practice. Pain. doi: 10.1016/j.pain.2010.11.017
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The Stabilizing Role of the Diaphragm

2/1/2011

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Study Title: Stabilizing Function of the Diaphragm: Dynamic MRI and Synchronized Spirometric Assessment
Authors: P Kolar, J Sulc, M Kyncl et al.
Journal: Journal of Applied Physiology
Date: August 2010

Summary:
  • For those of you who are familiar with DNS, PRI, NMT, FMS or any other system that places great emphasis on the importance of the diaphragm for postural stability of the locomotor system, here is a good article that identifies one mechanism behind this phenomenon. Pavel Kolar and friends utilized dynamic MRI to examine diaphragmatic excursion and positioning during tidal breathing and under load with isometric extremity movement. Along with spirometric evaluation, the objective of this study was also to examine the the dual respiratory and postural function of this important muscle. In studying thirty healthy subjects it was revealed that in comparison with tidal breathing, diaphragmatic excursion increases in the presence of both upper and extremity load. However, it should be noted that unlike many other muscles within the human body, the function of the diaphragm does not seem to function as one entire unit during stabilization. The investigators revealed that the highest level of excursion occurred at its apex and posterior fibers. Further, in comparison between upper and lower extremity loads, diaphragmatic tonicity and excursion was greater with lower extremity loads. Not surprising since it is not atypical for the lower extremity to warrant a greater load than that of the upper extremity. From these results, it was suggested that this muscle contributes to spinal stability via a hydraulic effect on the abdominal cavity thereby increasing intra abdominal pressure.

Kolar, P et al. (2010). Stabilizing function of the diaphragm: Dynamic MRI and synchronized spirometric assessment. Journal of Applied Physiology, 109; 1064-1071
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Return to Play in Sport

1/27/2011

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Study Title: Return-to-Play in Sport: A Decision-Based Model
Authors: DW Creighton, I Shrier, R Shultz, WH Meeuwisse & GO Matheson
Journal: Clinical Journal of Sport Medicine
Date: September 2010

Summary:
  • For those of you involved in sport medicine, here is an excellent example of scientific insight into the factors that may influence and determine Return to Play decision making.  This paper, authored by individuals at Stanford University, McGill University and the University of Calgary, details the all important, multifactorial decision making process of allowing an athlete to return to “full participation in sport without restriction”.  Through a literature synthesis, a model that included the Evaluation of Health Status, Evaluation of Participation Risk, and Decision Modification was proposed.  While the authors noted that the ability to quantify several decision elements may be limited, they suggested that decision modification must only be considered once participation risk is determined.
  • Although seemingly short and straightforward, this paper provides comprehensive insight into the variables that must be considered by those in a priviledged position to determine whether or not an athlete is permitted, let alone mentally and/or physically capable of, returning to sport.

Complete resolution of symptoms "cannot be considered in isolation” when determining return to play

Creighton DW, Shrier I, Shultz R, Meeuwisse WH & Matheson GO. (2010). Return-to-play in sport: A decision-based model. Clinical Journal of Sport Medicine, 20(5); 379-385
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Cryotherapy for Muscle Weakness Following Joint Injury

1/11/2011

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Study Title: Cryotherapy to Treat Persistent Muscle Weakness After Joint Injury
Authors: C. Kuenze & J.M. Hart
Journal: The Physician and Sportsmedicine
Date: October, 2010

Summary:
  • This paper reviewed the potential beneficial effect of cryotherapy on a common clinical entity beyond that of pain or inflammation...muscle weakness. While muscle weakness following joint injury may be a product of a multitude of factors upstream of simple reflex inibition mechanisms, "arthrogenic muscle inhibition" caused by structural damage and / or effusion may nonetheless persist throughout post-injury rehabilitation and recover. Of particular concern is the potential for high-threshold or compensatory muscle activity when specific muscles being exercised are unable to fully activate. The authors of this paper reviewed several studies looking at the approach of cryotherapy on AMI. From the limited existing literature available, it was revealed that pre-rehabilitative cryotherapy may have a transient, disinhibitory efect on muscle recruitment ability. That while the mechanism of such intervention has still yet to be ascertained with certainty, the application of 20-30 minutes of "cryotherapy prior to therapeutic exercise (may) provide a method for clinicians to open the motoneuron pool prior to exercise to maximize effectiveness."

Kuenze, C. & Hart, J.M. (2010). Cryotherapy to treat muscle weakness after joint injury. The Physician and Sportsmedicine, 3 (38), 38-42.
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The effect of A.R.T on pain thresholds

1/3/2011

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Study Title: Immediate effect on pain thresholds using active release technique on adductor strains: Pilot study.
Authors: A. Robb & J. Pajaczkowski
Journal: Journal of Bodywork & Movement Therapies
Date: January 2011

Summary:
  • Here is a nice little pilot study by two of my colleagues from Toronto on the effect of Active Release Techniques on immediate pain thresholds in elite ice hockey players. Using 9 players from AAA to the major junior level, they studied the influence of this popular manual therapy technique on its ability to modulate reported pain pressure thresholds (PPT) in acute adductor muscle strains. Up until now, the majority of the current literature on this technique had looked at the beneficial application of ART through case studies, however, few if any have looked deeper into the therapeutic effect of such protocols. PPT, "the minimal amount of pressure applied to the tissue to change the pressure sensation to discomfort or pain",  was assessed both pre- and post-treatment via a hand-held mechanical pressure algometer. A significant improvement in PPT was demonstrated in this study. Since the painful experience involves both a bottom-up and top-down process, this study sheds some light into the potential positive effects manual therapy may have in acute pain patients. While the authors disclose that it is still difficult to conclude with certainty the exact pathophysiological and histological mechanisms responsible for these outcomes, they do provide some potential mechanisms for such reduction of pain. Certainly this study lacked a large sample size and randomization (hence a pilot study), however, the work of Drs. Robb and Pajaczkowski do pave the way for further research to validate a therapy that carries with it an extreme wealth of anecdotal evidence.

Robb, A. & Pajaczkowski, J. (2011). Immediate effect on pain thresholds using active release technique on adductor strains: Pilot study. Journal of Bodywork and Movement Therapies, 15, 57-62
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Low Back Pain in Young Athletes

1/2/2011

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Study Title: Low back pain in young athletes
Authors: L. Purcell & L. Micheli
Journal: Sports Health
Date: May / June 2009

Summary:
  • A simple and straightforward literature review of orthopaedic causes of low back pain in young athletes. Utilizing a search of the current evidence through Medline, the authors briefly summarized the risk factors, clinical examination process, and prevention of such conditions in youth sport. A larger section of this paper was devoted to specific orthopaedic considerations including, but not limited to; spondylolysis, spondylolysthesis, posterior element overuse syndromes, and vertebral body apophyseal avulsion fractures. Interestingly, little credit was given to functional diagnoses although it was suggested that greater risk for injury may be present during periods of rapid growth. One of the recommendations given, to which I believe may be insufficient, was that "a patient who has resumed full pain-free activities...is considered clinically healed". Given the current lifestyle in which young athletes live, I believe more attention should be paid to the athletes' normal activities of daily living...or lack thereof!

Purcell, L. & Micheli, L. (2009). Low back pain in young athletes. Sports Health. Vol. 1 (3): 212-222
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Hamstring Length and the Patellofemoral Joint

10/14/2010

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This past week my most recent review was posted on Research Review Service, a site specifically for health care professionals of manual and rehabilitative therapy. The Influence of Reduced Hamstring Length on Patellofemoral Joint Stress During Squatting in Healthy Male Adults by Whyte et al was published earlier this year in Gait Posture.

Here's a brief summary of the study:

Study Purpose:
  • To determine the presence of a relationship between hamstring length and PFJ stress at 3 specific knee joint angles of flexion.

Study Population:
  • 16 recreationally active males divided into two groups based on knee joint angle-measured hamstring length.

Methodology:
  • A biomechanical model incorporating knee joint angle, knee extensor moment, and PFJ contact area was used to quantify PFJ stress.
  • MRI and 3D motion analyses were also utilized in this study.
  • A one-way ANOVA to determine the variations in PFJ stress between the 2 groups (with and without reduced hamstring length) was used.

Main Findings:
  • Patellofemoral Joint stresses differed significantly between the two groups at specific angles of knee flexion.
  • No significant differences in hip angles between the two groups.

Clinical Application:
  • This study demonstrated that subjects with reduced hamstring lengths have increased PFJ stress during various positions of the squatting movement.  As a result, such a decrease in length MAY contribute to the pathogenesis of various conditions relating to the knee.
  • These results enable us to consider another factor when managing those with knee pathology.

For a complete and "evidence-informed" understanding of the study, check out my review. I have obviously left out specifics from this study in this post as Research Review Service is a paid membership site. However, if you would like more information, please do not hesitate to ask.
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Motor Learning and Neuroplasticity in Rehabilitation

8/23/2010

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Here's a brief summary of an excellent paper by Boudreau et al from Manual Therapy. 

The purpose of this paper was to summarize several important aspects of motor-skill training for enhancing musculoskeletal rehabilitation.

Cortical Neuroplasticity:
 a dynamic feature of life that encompasses functional or morphological change in properties of neurons (connection strength, represenational patterns, neuron reorganization.
  • Positive changes: improvements in motor performance
  • Negative changes: decreases in performance, such as in the presence of chronic pain (low back pain resulting in decreased cortical spinal drive in lumbar musculature and subsequent shift in somatosensory representation)

It is hypothesized that motor-skill training can influence the direction of change in cortical neuroplasticity.
  • That is, the representation of muscles affected by pain in the sensorimotor system.

Potential effects of motor-skill training:
  • Improvements in task performance
  • Improvements secondary to very short training intervals.
  • Improvements occuring in two stages - 1) fast learning (following a single training session); 2) slower learning (across several sessions of practice)
  • Improvements with activation of inhibited/delayed musculature via repeated voluntary contractions.

Methods of Optimizing Rehabilitation:
  • Skilled training - skilled/precision tasks (vs strength training) should be performed to facilitate neuroplastic changes, and subsequently improvements in motor behaviour.
  • Negative effects of the presence of pain during novel motor skill acquisition - since pain alters excitability of the primary motor cortex in a rapid manner, these responses are generally protective and counterintuitive in the motor-learning process. Negative effects are also demonstrated in the presence of low quality sleep, stress, and attention deficits. Therefore, motor-skill learning should be relatively pain free.
  • Protective effect of motor-skill training - training prior to acute experimental pain may prevent unwanted cortical neuroplastic changes.
  • Cognitive effort - the greater the complexity of a skilled task and its corresponding intent, results in greater cortical representation and changes.
  • Quality - since no difference seems to exist with greater repetitions of within-session skill learning tasks, the primary focus of each rehabilitation session should be quality of performance.

The above information was derived from a multitude of studies and demonstrates that motor-skill training may positively influence cortical neuroplasticity in musculoskeletal rehabilitation
​
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