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Rachele E. Vogelpohl and Roger O. Kollock

Context:

Shoulder injury in baseball pitchers is a very common problem and has been linked to an imbalance in rotator cuff strength. Recently, the use of functional shoulder strength ratios has become more popular because they more closely resemble the actions of the shoulder during the throwing motion.

Objective:

To investigate the link between preseason shoulder rotator cuff functional strength ratios and the development of shoulder pain and injury.

Design:

Prospective research design.

Setting:

University human performance laboratory.

Patients:

Fifteen collegiate baseball pitchers participated in this study. At the end of the baseball season, six (19.5 ± 1.8 years, 73.6 ± 2.8 inches, 198.7 ± 19.1 lbs) developed shoulder injury and were placed in the injured group, and nine (21.0 ± 1.7 years, 73.1 ± 2.3 inches, 207.9 ± 28.1 lbs) did not develop injury and were placed in the noninjured group.

Interventions:

Isokinetic peak torque was collected concentrically and eccentrically for both shoulder internal rotation (IR) and external rotation (ER) at 60°-s−1, 180°-s−1, and 300°-s−1.

Main Outcome Measure:

The following functional ratios were calculated from the peak torque measures: concentric ER: concentric IR; eccentric ER: eccentric IR; concentric ER: eccentric IR (cocking phase); and eccentric ER: concentric IR (acceleration phase). Analysis was conducted using an analysis of variance comparing the injured and noninjured groups. A secondary analysis was conducted using an analyses of variance on the concentric and eccentric peak torque for shoulder IR and ER between groups.

Results:

The acceleration phase functional shoulder ratio was significantly higher (p = .019) in the injured group and a concentric IR peak torque (p = .003) was significantly lower in the injured group compared with the noninjured group.

conclusion:

Increased acceleration phase ratios and decreased concentric IR peak torque may be linked to the development of shoulder injury during a baseball season.

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Jaak Jürimäe

Physical exercise is known to regulate energy balance. Important to this regulatory system is the existence of several peptides that communicate the status of body energy stores to the brain and are related to the body fatness including leptin, adiponectin and ghrelin. These hormones assist in regulating energy balance as well as somatic and pubertal growth in children. It appears that rather few studies have investigated the responses of leptin, adiponectin and ghrelin to acute exercise and these studies have demonstrated no changes in these peptides as a result of exercise. Leptin levels are decreased and may remain unchanged advancing from prepuberty to pubertal maturation in young male and female athletes. A limited number of studies indicate that adiponectin levels are not different between prepubertal and pubertal athletes and untrained controls. However, in certain circumstances circulating adiponectin could be increased in young athletes after onset of puberty as a result of heavily increased energy expenditure. Ghrelin levels are elevated in young sportsmen. However, pubertal onset decreases ghrelin levels in boys and girls even in the presence of chronically elevated energy expenditure as seen in young athletes. Ghrelin may also be used as an indicator of energy imbalance across the menstrual cycle in adolescent athletes. There are no studies with high-molecular-weight adiponectin and only very few studies with acylated ghrelin responses to acute exercise and chronic training have been performed in young athletes. Since these forms of adiponectin and ghrelin have been thought to be bioactive forms, further studies with these specific forms of adiponectin and ghrelin are needed. In conclusion, further studies should be conducted to investigate the response of these hormones to acute and chronic negative energy balance to better understand their role in regulating energy balance during growth and maturation in young athletes.

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Cyril Genevois, Philippe Berthier, Vincent Guidou, Franck Muller, Boris Thiebault and Isabelle Rogowski

Context:

In women's handball, the large numbers of throws and passes make the shoulder region vulnerable to overuse injuries. Repetitive throwing motions generate imbalance between shoulder internal- and external-rotator muscles. It has not yet been established whether sling-based training can improve shoulder external-rotator muscle strength.

Objective:

This study investigated the effectiveness of a 6-wk strengthening program in improving shoulder functional profile in elite female high school handball players.

Design:

Crossover study.

Setting:

National elite handball training center.

Participants:

25 elite female high school handball players.

Interventions:

The program, completed twice per week for 6 wk, included sling-based strengthening exercises using a suspension trainer for external rotation with scapular retraction and scapular retraction alone.

Main Outcomes:

Maximal shoulder external- and internal-rotation strength, shoulder external- and internal-rotation range of motion (ROM), and maximal throwing velocity were assessed preintervention and postintervention for dominant and nondominant sides.

Results:

After sling training, external- and internal-rotation strength increased significantly for both sides (P ≤ .001, and P = .004, respectively), with the result that there was no significant change in external- and internal-rotation strength ratios for either the dominant or the nondominant shoulder. No significant differences were observed for external-rotation ROM, while internal-rotation ROM decreased moderately, in particular in the dominant shoulder (P = .005). Maximal throwing velocity remained constant for the dominant arm, whereas a significant increase was found for the nondominant arm (P = .017).

Conclusions:

This 6-wk strengthening program was effective in improving shoulder external-rotator muscle strength but resulted in a decrease in the ROM in shoulder internal rotation, while throwing velocity remained stable. Adding a stretching program to this type of sling-based training program might help avoid potential detrimental effects on shoulder ROM.

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Ruth L. Chimenti, Sara A. Scholtes and Linda R. Van Dillen

Many risk factors have been identified as contributing to the development or persistence of low back pain (LBP). However, the juxtaposition of both high and low levels of physical activity being associated with LBP reflects the complexity of the relationship between a risk factor and LBP. Moreover, not everyone with an identified risk factor, such as a movement pattern of increased lumbopelvic rotation, has LBP.

Objective:

The purpose of this study was to examine differences in activity level and movement patterns between people with and people without chronic or recurrent LBP who participate in rotation-related sports.

Design Case:

Case-control study.

Setting:

University laboratory environment.

Participants:

52 people with chronic or recurrent LBP and 25 people without LBP who all play a rotation-related sport.

Main Outcome Measures:

Participants completed self-report measures including the Baecke Habitual Activity Questionnaire and a questionnaire on rotation-related sports. A 3-dimensional motion-capture system was used to collect movement-pattern variables during 2 lower-limb-movement tests.

Results:

Compared with people without LBP, people with LBP reported a greater difference between the sport subscore and an average work and leisure composite subscore on the Baecke Habitual Activity Questionnaire (F = 6.55, P = .01). There were no differences between groups in either rotation-related-sport participation or movement-pattern variables demonstrated during 2 lower-limb-movement tests (P > .05 for all comparisons).

Conclusions:

People with and people without LBP who regularly play a rotation-related sport differed in the amount and nature of activity participation but not in movement-pattern variables. An imbalance between level of activity during sport and daily functions may contribute to the development or persistence of LBP in people who play a rotation-related sport.

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Claire Blennerhassett, Lars R. McNaughton, Lorcan Cronin and S. Andy Sparks

The nutritional intake of ultraendurance athletes is often poorly matched with the requirements of the sport. Nutrition knowledge is a mediating factor to food choice that could correct such imbalances. Therefore, the purpose of this study was to develop and validate a questionnaire to assess the nutrition knowledge of ultraendurance athletes. Nutritional knowledge was assessed using a modified sports nutrition knowledge questionnaire (ULTRA-Q). Four independent assessors with specialization in sports nutrition confirmed the content validity of the ULTRA-Q. Registered sports nutritionists, registered dietitians, and those without nutrition training completed the ULTRA-Q on two separate occasions. After the first completion, a significant difference in nutrition scores between groups (p ≤ .001) provided evidence of construct validity. After the second completion, intraclass correlation coefficients comparing nutrition scores between time points (.75–.95) provided evidence of test–retest reliability. Subsequently, experienced ultraendurance athletes (male: n = 74 and female: n = 27) completed the ULTRA-Q. Athletes also documented their sources of nutrition knowledge for ultraendurance events. The total nutrition knowledge score for ultraendurance athletes was 68.3% ± 9.5%, and there were no significant differences in knowledge scores between males and females (67.4% ± 9.6% and 70.7% ± 9.3%, respectively) or between runners and triathletes (69.1% ± 9.7% and 65.1% ± 9.4%, respectively). In general, it appeared that ultraendurance athletes favored other athletes (73%) over nutrition experts (8%) as a source of nutritional information. The findings of this study indicate that ultraendurance athletes had a reasonable level of nutrition knowledge, but interathlete variability suggests a need for targeted nutrition education.

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Alessandra Paiva de Castro, José Rubens Rebelatto and Thaís Rabiatti Aurichio

Context:

Wearing inappropriate shoes can cause biomechanical imbalance, foot problems, and pain and induce falls.

Objective:

To verify the prevalence of wearing incorrectly sized shoes and the relationship between incorrectly sized shoes and foot dimensions, pain, and diabetes among older adults.

Design:

A cross-sectional study.

Participants:

399 older adults (227 women and 172 men) age 60 to 90 y.

Main Outcome Measures:

The participants were asked about the presence of diabetes, pain in the lower limbs and back, and pain when wearing shoes. Foot evaluations comprised the variables of width, perimeter, height, length, first metatarsophalangeal angle, the Arch Index, and the Foot Posture Index. The data analysis was performed using a 2-sample t test and chi-square test.

Results:

The percentage of the participants wearing shoe sizes bigger than their foot length was 48.5% for the women and 69.2% for the men. Only 1 man was wearing a shoe size smaller than his foot length. The older adults wearing the incorrect shoe size presented larger values for foot width, perimeter, and height than those wearing the correct size, but there were no significant differences between the groups with respect to the Arch Index and the Foot Posture Index. Incorrectly sized shoes were associated with ankle pain in women but not with diabetes. Men were more likely to wear incorrectly fitting shoes. The use of correctly sized shoes was associated with back pain in women.

Conclusions:

The use of incorrectly sized shoes was highly prevalent in the population studied and was associated with larger values for foot width, perimeter, and height and with ankle pain.

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Elizabeth E. Hibberd, Sakiko Oyama, Jeffrey T. Spang, William Prentice and Joseph B. Myers

Context:

Shoulder injuries are common in swimmers because of the demands of the sport. Muscle imbalances frequently exist due to the biomechanics of the sport, which predispose swimmers to injury. To date, an effective shoulder-injury-prevention program for competitive swimmers has not been established.

Objective:

To assess the effectiveness of a 6-wk strengthening and stretching intervention program on improving glenohumeral and scapular muscle strength and scapular kinematics in collegiate swimmers.

Design:

Randomized control trial.

Setting:

University biomechanics research laboratory.

Participants:

Forty-four Division I collegiate swimmers.

Interventions:

The intervention program was completed 3 times per week for 6 wk. The program included strengthening exercises completed using resistance tubing—scapular retraction (Ts), scapular retraction with upward rotation (Ys), scapular retraction with downward rotation (Ws), shoulder flexion, low rows, throwing acceleration and deceleration, scapular punches, shoulder internal rotation at 90° abduction, and external rotation at 90° abduction—and 2 stretching exercises: corner stretch and sleeper stretch.

Main Outcome Measurements:

Scapular kinematics and glenohumeral and scapular muscle strength assessed preintervention and postintervention.

Results:

There were no significant between-groups differences in strength variables at pre/post tests, although shoulder-extension and internal-rotation strength significantly increased in all subjects regardless of group assignment. Scapular kinematic data revealed increased scapular internal rotation, protraction, and elevation in all subjects at posttesting but no significant effect of group on the individual kinematic variables.

Conclusions:

The current strengthening and stretching program was not effective in altering strength and scapular kinematic variables but may serve as a framework for future programs. Adding more stretching exercises, eliminating exercises that overlap with weight-room training and swim training, and timing of implementation may yield a more beneficial program for collegiate swimmers.

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Jordan Bettleyon and Thomas W. Kaminski

Clinical Scenario: Low-level laser therapy (LLLT) is a controversial topic for its use in athletic recovery, mainly due to inconsistency in research regarding the application of LLLT. Articles on LLLT have assessed its effectiveness in untrained humans through pain scales, functional scales, and blood draws, and it has been found capable in nonathletic rehabilitative use. The controversy lies with LLLT in the recovering athlete. Not only do athletes need to perform at high levels, but each sport is unique in the metabolic demands placed on the athletes’ bodies. This modality can alter chemical mediators of the inflammatory process, specifically blood lactate (BL) and creatine kinase (CK). During soccer contests, it is a common problem for athletes to have an average CK level of 800 U/L and BL of 8 mmol·L, increasing delayed-onset muscle soreness and fatigue. Micro-CK level elevation is associated with cellular membrane damage, localized hypoxia, and electrolyte imbalances, hindering the recovery process. Clinical Question: Does LLLT decrease muscle-damaging mediators effecting player fatigue and delayed-onset muscle soreness after performance in soccer athletes versus sham treatment? Summary of Key Findings: In 3 studies, preperformance, postperformance, or preperformance and postperformance LLLT was performed and evaluated BL (2 of 3) and CK (2 of 3). In each article, BL and CK showed a significant decrease (P < .05) when performed either preperformance or postperformance versus the control group. The greatest decrease in these mediators was noticed when postperformance laser therapy was performed. Clinical Bottom Line: LLLT at 10, 30, or 50 J performed at a minimum of 2 locations on the rectus femoris, vastus lateralis, and vastus medialis bilaterally for 10 seconds each is significant in decreasing blood serum levels of BL and CK when performed postexercise. Strength of Recommendations: All 3 articles obtained a Physiotherapy Evidence Database score of ≥8/10.

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Scott K. Lynn, Ricardo A. Padilla and Kavin K.W. Tsang

Context:

Proper functioning of the intrinsic foot musculature (IFM) is essential in maintaining the integrity of the medial longitudinal arch (MLA). Improper functioning of the IFM leads to excessive pronation of the foot, which has been linked to various pathologies. Therefore, training the IFM to avoid excessive pronation may help prevent some of these pathologies; however, it is not clear how to train these muscles optimally.

Objective:

To investigate the effects of 2 different types of IFM training on the height of the MLA and static- and dynamic-balance task performance.

Design:

Randomized controlled trial, repeated-measures mixed-model design.

Setting:

University biomechanics laboratory for testing and a home-based training program.

Participants:

24 healthy, university-age volunteers (3 groups of 8) with no history of major lower limb pathology or balance impairment.

Interventions:

One experimental group performed 4 wk of the short-foot exercise (SFE) and the other performed 4 wk of the towel-curl exercise (TCE). Participants were asked to perform 100 repetitions of their exercise per day.

Main Outcome Measures:

Navicular height during weight bearing, the total range of movement of the center of pressure (COP) in the mediolateral (ML) direction for a static-balance test and a dynamic-balance test.

Results:

There were no differences in the navicular height or static-balance tests. For the dynamic-balance test, all groups decreased the ML COP movement on the dominant limb by a small amount (~5 mm); however, the SFE group was able to decrease COP movement much more than the TCE group in the nondominant limb.

Conclusions:

The SFE appeared to train the IFM more effectively than the TCE; however, there were differing results between the dominant and nondominant legs. These imbalances need to be taken into consideration by clinicians.

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and imbalance will most likely benefit only from vestibular rehabilitation. a. True b. False 3. Due to a lack of consistency in exercise prescription and administration, it is difficult to make meaningful assertions about the effect of vestibular rehabilitation on resolving dizziness and imbalance. a