Edward R. Laskowski

Differences in repositioning error among patients with low back pain compared with control subjects

Study Design. Trunk repositioning error was measured in 20 patients with chronic low back pain and 20 control subjects. Objectives. To measure trunk repositioning error as a method of measuring proprioception of the low back and to compare trunk repositioning error in patients with low back pain and in control subjects. Summary of Background Data. Although many current low back pain rehabilitation programs incorporate proprioceptive training, very little research has been performed on proprioception of the low back. Methods. While standing with the legs and pelvis immobilized, the subject bent the trunk to a predetermined target position and then attempted to replicate the position. Repositioning error was calculated as the absolute difference between the actual target position and the subject-perceived target position. The multiple target positions in the frontal and sagittal planes were tested. Trunk position was measured with a 3Space Tracker, which analyzes the three-dimensional position of the body. Results. Repositioning error in patients with low back pain was significantly higher than that of control subjects in flexion, and significantly lower than that of control subjects in extension. Conclusions. The increase in repositioning error of patients with low back pain during flexion implies that some aspects of proprioception are lost in patients with low back pain. The decrease in repositioning error in patients with low back pain in extension is not as easily explained, but could possibly be caused by increased activation of mechanoreceptors in facet joints.

Ankle Disk Training Influences Reaction Times of Selected Muscles in a Simulated Ankle Sprain

Ankle disk training has been used as an exercise in sports medicine clinics to help protect against ankle sprains. This study investigated the effects of ankle disk training on the contraction pattern of the anterior tibialis, posterior tibialis, peroneus longus, and flexor digitorum longus muscles in a simulated ankle sprain. Twenty adults were recruited and divided into a control group and an experimental group. A platform with a trapdoor was used to simulate a lateral ankle sprain. Electromyographic data were recorded from each sub ject in pretraining and posttraining tests. The experi mental group underwent ankle disk training for 8 weeks between the pretraining and posttraining tests. In the pretraining test, the four muscles started to contract simultaneously; in the posttraining test, the contrac tions of the anterior and posterior tibialis muscles were delayed. This delay favors the correction of excessive ankle inversion. This study examined the effects of one form of proprioceptive training on muscle reaction times, and its results may explain why such training can help protect against ankle sprains.

The Effect of Ankle Disk Training on Muscle Reaction Time in Subjects with a History of Ankle Sprain

The purpose of this study was to determine whether 8 weeks of ankle disk training alters ankle muscle onset latency of patients with a history of lateral ankle sprain. The training was completed by eight minimally symptomatic subjects with a history of nonrehabilitated, unilateral, inversion ankle sprain sustained between 6 and 16 months before entry into the study. Ankle inversion perturbations monitored by fine-wire electromyography were performed in four lower extremity muscles (anterior tibialis, posterior tibialis, peroneus longus, and flexor digitorum longus) of all subjects on both the injured (experimental) and noninjured (control) legs. Testing was performed at study entry and after 8 weeks of ankle disk training on the previously injured ankle. Results revealed a statistically significant decrease in the anterior tibialis onset latency in both the experimental (67.6 ± 20.3 to 51.7 ± 17.6) and control (65.5 ± 9.8 to 53.8 ± 23.7) ankles after the training period. These findings indicate that muscle onset latency decreases in specific ankle muscle groups after ankle disk training in previously injured ankles. Both the experimental and control ankles demonstrated a significant change, which raises the question as to whether a proprioceptive cross-training effect occurred.

Corticosteroid injection in early treatment of lateral epicondylitis.

ObjectiveTo analyze whether a corticosteroid injection in combination with rehabilitation early in the course of lateral epicondylitis (LE) alters the outcome up to 6 months after injection compared with a control injection and rehabilitation. DesignRandomized, controlled, double-blind study. SettingSports medicine center in a tertiary care center. Participantsubjects with a diagnosis of LE whose symptoms had been present less than 4 weeks were included. Subjects were recruited by word of mouth and through advertising. The 39 subjects who were recruited were 18 to 65 years old. Interventions19 subjects were randomized to receive rehabilitation and a sham injection, and 20 were randomized to receive rehabilitation and a corticosteroid injection. At 4 and 8 weeks, they were reevaluated and their treatment programs were modified, if indicated. Main Outcome MeasuresOutcome measurements were performed at baseline, 4 weeks, 8 weeks, and 6 months, and included a functional pain questionnaire and a visual analogue pain scale. Painless grip strength on the affected side and maximal grip strength bilaterally were measured at baseline, 4 weeks, and 8 weeks. ResultsThere were no significant differences in outcome between the two groups with the exception of an improvement in the visual analogue pain scale in the corticosteroid group from 8 weeks to 6 months. Outcome measurements in both groups improved significantly over time; more than 80% of subjects reported improvements from baseline to 6 months for all scales. ConclusionA corticosteroid injection does not provide a clinically significant improvement in the outcome of LE, and rehabilitation should be the first line of treatment in patients with a short duration of symptoms.

Repositioning error in low back pain: Comparing trunk repositioning error in subjects with chronic low back pain and control subjects

Study Design. Repositioning error of the trunk was tested in 20 subjects with chronic low back pain and in 20 control subjects. The 3Space Tracker (Polhemus, Colchester, VT), a device that measures three-dimensional position in space, was used to determine the subject’s trunk position. Objectives. To determine whether repositioning error is different in subjects with chronic low back pain than in control subjects. Summary of Background Data. Proprioception allows the body to maintain proper orientation during static and dynamic activities. In peripheral joint injuries, researchers have demonstrated a loss of some aspects of proprioception and improvement in outcome with retraining. Although the components of proprioception in subjects with low back pain have not been well studied, it is thought that these persons lose some elements of proprioception that can be measured in a quantifiable way. If so, then rehabilitation to improve these deficits is important. In this pilot study, one aspect of proprioception, repositioning error, was examined. Methods. The subjects attempted to replicate target positions of the trunk in flexion, extension, lateral bending, and lateral rotation. Repositioning error was calculated as the absolute difference between the actual and the subject-replicated target positions. Results. No significant difference was found in repositioning error between the control subjects and the persons with chronic low back pain. Conclusions. Because proprioception is complex and entails the use of many afferent receptors, it is difficult to measure any one afferent deficiency discretely. The authors believe that this study, in which one aspect of proprioception was measured in an indirect manner, provides important background information on low back position sense. Further studies analyzing aspects of proprioception in subjects with low back pain are recommended.

The 'yips' in golf: a continuum between a focal dystonia and choking.

AbstractThe definition of the ‘yips’ has evolved over time. It is defined as a motor phenomenon of involuntary movements affecting golfers. In this paper, we have extended the definition to encompass a continuum from the neurologic disorder of dystonia to the psychologic disorder of choking. In many golfers, the pathophysiology of the ‘yips’ is believed to be an acquired deterioration in the function of motor pathways (e.g. those involving the basal ganglia) which are exacerbated when a threshold of high stress and physiologic arousal is exceeded. In other golfers, the ‘yips’ seems to result from severe performance anxiety. Physically, the ‘yips’ is manifested by symptoms of jerks, tremors or freezing in the hands and forearms. These symptoms can result in: (i) a poor quality of golf performance (adds 4.9 strokes per 18 holes); (ii) prompt use of alcohol and β-blockers; and (iii) contribute to attrition in golf. Golfers with the ‘yips’ average 75 rounds per year, although many ‘yips’-affected golfers decrease their playing time or quit to avoid exposure to this embarrassing problem. While more investigation is needed to determine the cause of the ‘yips’, this review article summarises and organises the available research. A small study included in this paper describes the ‘yips’ phenomenon from the subjective experience of ‘yips’-affected golfers. The subjective experience (n = 72) provides preliminary support for the hypothesis suggesting that the ‘yips’ is on a continuum. Based on the subjective definitions of 72 ‘yips’-affected golfers, the ‘yips’ was differentiated into type I (dystonia) and type II (choking). A theoretical model provides a guide for future research on golfers with either type I or type II ‘yips’.

An Eccentric- and Concentric-Strength Profile of Shoulder External and internal Rotator Muscles in Professional Baseball Pitchers

The purpose of this study was to establish a data base on the isokinetic eccentric muscular performance char acteristics of external and internal rotator muscles in the shoulders of professional baseball pitchers. Con centric data are also included and compared with pre viously published concentric studies. Twenty-five pro fessional baseball pitchers were evaluated with a Kin- Com isokinetic dynamometer. The subjects tested had a mean age of 23.5 years and a mean body weight of 199 pounds. Eccentric and concentric isokinetic tests were performed at 60 and 120 deg/sec. The testing protocol was standardized for each subject. Test re sults indicated no statistically significant difference in mean torque between throwing and nonthrowing shoulders for either external or internal rotator muscle groups. Eccentric strength was significantly greater than concentric strength for all muscle groups tested. The external-to-internal rotator muscle strength ratios were well above those previously published for high school through professional pitchers. Mean torque-to- lean body weight ratios were also included to establish a data base. This study establishes one of the first data bases for eccentric isokinetic muscle strength of shoul der rotator muscles in professional baseball pitchers. The data may help clinicians prevent and rehabilitate shoulder injuries in professional throwing athletes.

Refining rehabilitation with proprioception training: expediting return to play.

Although definitions of proprioception sense of joint position may vary, its importance in preventing and rehabilitating athletic injury remains constant: Restoring it after injury allows the body to maintain stability and orientation during static and dynamic activities. Any type of joint injury can interrupt position sense. Proprioceptive programs need to be tailored to the individual patient, but exercises can include balance training, closed-kinetic-chain exercises such as the leg press or single-leg hops, back-strengtheners, and quadruped stabilization. Sport-specific training is also crucial in regaining proprioception; an example is defensive slide drills in basketball.

A multidisciplinary study of the 'yips' phenomenon in golf: An exploratory analysis

AbstractBackground: The ‘yips’ is a psychoneuromuscular impediment affecting execution of the putting stroke in golf. Yips symptoms of jerks, tremors and freezing often occur during tournament golf and may cause performance problems. Yips-affected golfers add approximately 4.7 strokes to their scores for 18 holes of golf, and have more forearm electromyogram activity and higher competitive anxiety than nonaffected golfers in both high and low anxiety putting conditions. The aetiology of the yips is not clear. Objective: To determine whether the yips is a neurological problem exacerbated by anxiety, or whether the behaviour is initiated by anxiety and results in a permanent neuromuscular impediment. Methods: In phase I, golf professionals assisted investigators in developing a yips questionnaire that was sent to tournament players (<12 handicap) to establish the prevalence and characteristics of the yips. Phase II measured putting behaviour in scenarios that contribute to the yips response. Four self-reported yips and 3 nonaffected golfers putted 3 scenarios using an uncorrected grip and a standard length putter. Heart rate was superimposed on the videotape and the putter grip was instrumented with strain gauges to measure grip force. Electromyograms and relative putting performance were also measured. Results: The questionnaire was sent to 2630 tournament players, of whom 1031 (39%) responded (986 men and 45 women). Of these, 541 (52%) perceived they experienced the yips compared with 490 (48%) who did not.Yips-affected golfers reported that the most troublesome putts were 3, 4 and 2 feet (0.9, 1.2 and 0.6 metres) from the hole. Fast, downhill, left-to-right breaking putts and tournament play also elicited the yips response. Golfers affected by the yips had a faster mean heart rate, increased electromyogram activity patterns and exerted more grip force than nonaffected golfers and had a poorer putting performance. Conclusions: For <10 handicap male golfers and <12 handicap female golfers, the prevalence of the yips is between 32.5% and 47.7%, a high proportion of serious golfers. This high prevalence suggests that medical practitioners need to understand the aetiology of the yips phenomenon so that interventions can be identified and tested for effectiveness in alleviating symptoms. Although previous investigators concluded that the yips is a neuromuscular impediment aggravated but not caused by anxiety, we believe the yips represents a continuum on which ‘choking’ (anxiety-related) and dystonia symptoms anchor the extremes. The aetiology may well be an interaction of psychoneuromuscular influences. Future research to test the effect of medications such as β-blockers should assist in better identifying the contributions these factors make to the yips phenomenon.

Physical Activity, Quality of Life, and Burnout Among Physician Trainees: The Effect of a Team-Based, Incentivized Exercise Program

OBJECTIVE To prospectively study the effects of an incentivized exercise program on physical activity (PA), quality of life (QOL), and burnout among residents and fellows (RFs) in a large academic medical center. PARTICIPANTS AND METHODS In January 2011, all RFs at Mayo Clinic in Rochester, Minnesota (N=1060), were invited to participate in an elective, team-based, 12-week, incentivized exercise program. Both participants and nonparticipants had access to the same institutional exercise facilities. Regardless of participation, all RFs were invited to complete baseline and follow-up (3-month) assessments of PA, QOL, and burnout. RESULTS Of the 628 RFs who completed the baseline survey (59%), only 194 (31%) met the US Department of Health and Human Services recommendations for PA. Median reported QOL was 70 on a scale of 1 to 100, and 182 (29%) reported at least weekly burnout symptoms. A total of 245 individuals (23%) enrolled in the exercise program. No significant differences were found between program participants and nonparticipants with regard to baseline demographic characteristics, medical training level, PA, QOL, or burnout. At study completion, program participants were more likely than nonparticipants to meet the Department of Health and Human Services recommendations for exercise (48% vs 23%; P<.001). Quality of life was higher in program participants than in nonparticipants (median, 75 vs 68; P<.001). Burnout was lower in participants than in nonparticipants, although the difference was not statistically significant (24% vs 29%; P=.17). CONCLUSION A team-based, incentivized exercise program engaged 23% of RFs at our institution. After the program, participants had higher PA and QOL than nonparticipants who had equal exercise facility access. Residents and fellows may be much more sedentary than previously reported.