Motion of the multi-segmented spine in elite dancers during passé and arabesque.

BACKGROUND: The spinal biomechanics of dance tasks have received little study and no studies have used a multi-segmented spinal model. Knowledge of how the segments of the spine move may be useful to the dance clinician and dance educator. RESEARCH QUESTION: What is the direction and amount of motion of the primary segments of the spine in elite dancers during an arabesque and a passé? METHODS: This observational study examined 59 elite dancers performing an arabesque and a passé using a three-dimensional motion analysis system with the trunk divided into a series of five segments: pelvis, lower lumbar, upper lumbar, lower thoracic and upper thoracic spine. RESULTS: For the arabesque, all spinal segments moved in the same direction within each plane and the majority of total spinal motion occurred in the thoracic spine. Thoracic segments were at or near end range position at completion of the arabesque. For the passé, the spinal segments moved in different directions within each plane and the majority of total spinal motion occurred in the lumbar spine. SIGNIFICANCE: Dance clinicians and dance educators may benefit from the knowledge that thoracic hypomobility in any plane may limit arabesque performance and that attempts to instruct dancers to achieve a position of passé without flexion of the lumbar spine may be a valid aesthetic ideal but also an unrealistic functional expectation.

Multi-segment spine range of motion in dancers with and without recent low back pain.

BACKGROUND: Altered spine kinematics are a common in people with LBP. This may be especially true for populations such as dancers, who are required to perform repetitive movements of the spine, although this remains unclear. RESEARCH QUESTION: Do dancers with recent LBP display altered spine kinematics compared to their asymptomatic counterparts? METHODS: A cross-sectional study of multi-segment spine kinematics was performed. Forty-seven pre-professional and professional female dancers either with LBP in the past two months (n = 26) or no LBP in the past 12 months (n = 21) participated. Range of motion (ROM) during standing side bending, seated rotation, and walking gait were compared. RESULTS: Female dancers with LBP displayed reduced upper lumbar transverse plane ROM in seated rotation (Effect Size (ES)= -0.61, 95% Confidence Interval (CI): -1.20, 0.02, p = 0.04), as well as reduced lower lumbar transverse plane ROM (ES=-0.65, 95% CI: -1.24, -0.06, p = 0.03) in gait. However, there was increased lower thoracic transverse plane ROM (ES = 0.62, 95% CI: 0.04, 1.21, p = 0.04) during gait. No differences in the frontal plane were observed. SIGNIFICANCE: Altered transverse plane spine kinematics were evident in dancers with recent LBP for select segments and tasks. This may reflect a protective movement strategy. However, as the effect sizes of observed differences were moderate, and the total number of differences between groups was small, collectively, it seems only subtle differences in spine kinematics differentiate dancers with LBP to dancers without.

Comparison of lower limb stiffness between male and female dancers and athletes during drop jump landings.

Repetition of jumps in dance and sport training poses a potential injury risk; however, non-contact landing injuries are more common in athletes than dancers. This study aimed to compare the lower limb stiffness characteristics of dancers and athletes during drop landings to investigate possible mechanisms of impact-related injuries. Kinematics and kinetics were recorded as 39 elite modern and ballet dancers (19 men and 20 women) and 40 college-level team sport athletes (20 men and 20 women) performed single-legged drop landings from a 30-cm platform. Vertical leg stiffness and joint stiffness of the hip, knee, and ankle were calculated using a spring-mass model. Stiffness data, joint kinematics, and moments were compared with a group-by-sex 2-way analysis of variance. Multiple linear regression was used to assess the relative contribution of hip and knee and ankle joint stiffness to variance in overall vertical leg stiffness for dancers and athletes. Dancers had lower leg (P < 0.001), knee joint (P = 0.034), and ankle joint stiffness (P = 0.043) than athletes. This was facilitated by lower knee joint moments (P = 0.012) and greater knee (P = 0.029) and ankle joint (P = 0.048) range of motion in dancers. Males had higher leg (P < 0.001) and ankle joint stiffness (P < 0.001) than females. This occurred through lower ankle range of motion (P < 0.001) and greater ankle moment (P = 0.022) compared to females. Male and female dancers demonstrated reduced lower limb stiffness compared to athletes, indicating a more pliable landing technique. Dance training techniques could potentially inform approaches to injury prevention in athletes.

Upper cervical and upper thoracic manipulation versus mobilization and exercise in patients with cervicogenic headache: a multi-center randomized clinical trial.

BACKGROUND: Although commonly utilized interventions, no studies have directly compared the effectiveness of cervical and thoracic manipulation to mobilization and exercise in individuals with cervicogenic headache (CH). The purpose of this study was to compare the effects of manipulation to mobilization and exercise in individuals with CH. METHODS: One hundred and ten participants (n = 110) with CH were randomized to receive both cervical and thoracic manipulation (n = 58) or mobilization and exercise (n = 52). The primary outcome was headache intensity as measured by the Numeric Pain Rating Scale (NPRS). Secondary outcomes included headache frequency, headache duration, disability as measured by the Neck Disability Index (NDI), medication intake, and the Global Rating of Change (GRC). The treatment period was 4 weeks with follow-up assessment at 1 week, 4 weeks, and 3 months after initial treatment session. The primary aim was examined with a 2-way mixed-model analysis of variance (ANOVA), with treatment group (manipulation versus mobilization and exercise) as the between subjects variable and time (baseline, 1 week, 4 weeks and 3 months) as the within subjects variable. RESULTS: The 2X4 ANOVA demonstrated that individuals with CH who received both cervical and thoracic manipulation experienced significantly greater reductions in headache intensity (p < 0.001) and disability (p < 0.001) than those who received mobilization and exercise at a 3-month follow-up. Individuals in the upper cervical and upper thoracic manipulation group also experienced less frequent headaches and shorter duration of headaches at each follow-up period (p < 0.001 for all). Additionally, patient perceived improvement was significantly greater at 1 and 4-week follow-up periods in favor of the manipulation group (p < 0.001). CONCLUSIONS: Six to eight sessions of upper cervical and upper thoracic manipulation were shown to be more effective than mobilization and exercise in patients with CH, and the effects were maintained at 3 months. TRIAL REGISTRATION: NCT01580280 April 16, 2012.

Perceived Benefits of Yoga among Urban School Students: A Qualitative Analysis.

This study reports on the findings of a qualitative evaluation of a yoga intervention program for urban middle and high school youth in New York City public and charter schools. Six focus groups were conducted with students who participated in a year-long yoga program to determine their perceptions of mental and physical benefits as well as barriers and challenges. Results show that students perceived the benefits of yoga as increased self-regulation, mindfulness, self-esteem, physical conditioning, academic performance, and stress reduction. Barriers and challenges for a yoga practice include lack of time and space. The extent to which the benefits experienced are interrelated to one another is discussed. Suggestions for future research and school-based programming are also offered.

Yoga and Emotion Regulation in High School Students: A Randomized Controlled Trial.

Middle adolescents (15-17 years old) are prone to increased risk taking and emotional instability. Emotion dysregulation contributes to a variety of psychosocial difficulties in this population. A discipline such as yoga offered during school may increase emotion regulation, but research in this area is lacking. This study was designed to evaluate the impact of a yoga intervention on the emotion regulation of high school students as compared to physical education (PE). In addition, the potential mediating effects of mindful attention, self-compassion, and body awareness on the relationship between yoga and emotion regulation were examined. High school students were randomized to participate in a 16-week yoga intervention (n = 19) or regular PE (n = 18). Pre-post data analyses revealed that emotion regulation increased significantly in the yoga group as compared to the PE group (F (1,32) = 7.50, p = .01, and eta(2) = .19). No significant relationship was discovered between the changes in emotion regulation and the proposed mediating variables. Preliminary results suggest that yoga increases emotion regulation capacities of middle adolescents and provides benefits beyond that of PE alone.

A Randomised Controlled Trial Comparing the Impact of Yoga and Physical Education on the Emotional and Behavioural Functioning of Middle School Children.

BACKGROUND: Yoga programs geared for school children have become more widespread, but research regarding its impact on children is lacking. Several studies have reported positive outcomes, though there is a need for more randomised controlled trials. OBJECTIVES: To determine the effects of yoga on children's emotional and behavioural functioning when compared with physical education (PE) classes. METHODS: Thirty middle school children were randomised to participate in either a school-based Ashtanga-informed yoga or PE class three times a week for 12 weeks. Emotional (i.e. affect, self-perceptions) and behavioural (i.e. internalising and externalising problems, aggression) functioning were measured pre and post-intervention. RESULTS: There were no significant changes between groups in self-reported positive affect, global self-worth, aggression indices or parent reports of their children's externalising and internalising problems. However, negative affect increased for those children participating in yoga when compared to the PE program. CONCLUSIONS: In general, findings suggest that yoga and PE classes do not differentially impact on middle school children's emotional and behavioural functioning. However, children reported experiencing increased negative emotions after receiving yoga while children in the PE group reported a decrease in these feelings. Implications of these results and potential directions for future research on children's yoga are discussed.

Comparison of landing biomechanics between male and female dancers and athletes, part 2: Influence of fatigue and implications for anterior cruciate ligament injury.

BACKGROUND: Fatigue is strongly linked to an increased risk of injuries, including anterior cruciate ligament (ACL) ruptures. Part 1 of this study identified differences in the biomechanics of landing from a jump between dancers and team athletes, particularly female athletes, which may explain the epidemiological differences in ACL injuries between dancers and team athletes and the lack of a sex disparity within dancers. However, it is not known if these biomechanical variables change differently between team athletes and dancers in the face of fatigue. PURPOSE/ HYPOTHESIS: The purpose of this study was to compare dancers' and team athletes' resistance to fatigue and its effect on the biomechanics of single-legged drop landings. The primary hypotheses were that dancers may be more resistant than team athletes to the onset of fatigue and/or may have different biomechanical responses than athletes in landing tasks once fatigue has been achieved. STUDY DESIGN: Controlled laboratory study. METHODS: Kinematics and kinetics were recorded as 40 elite modern and ballet dancers (20 men and 20 women) and 40 team sport athletes (20 men and 20 women; National Collegiate Athletic Association Division I-III) performed single-legged drop landings from a 30-cm platform before and after a fatigue protocol consisting of step-ups and vertical jumps. Unfatigued and fatigued joint kinematics and kinetics were compared between groups and sexes with multivariate analyses of variance, followed by pairwise t tests as appropriate. RESULTS: Dancers took longer (P = .023) than team athletes to reach a similar state of fatigue. Multiple kinetic (eg, increased peak knee valgus moment; P < .001) and kinematic (eg, increased lateral and forward trunk flexion; P < .001 and P = .002, respectively) parameters of landing changed with fatigue, such that both fatigued dancers and athletes landed with mechanics that were more at risk for ACL injuries as compared with before fatigue. CONCLUSION: Dancers took significantly longer to reach fatigue than team athletes. Female athletes consistently exhibited landing patterns associated with a risk for ACL injuries when compared with the other 3 groups. Fatigue changed landing mechanics similarly in both dancers and athletes, such that all groups landed with worse alignment after being fatigued. CLINICAL RELEVANCE: Dancers are more resistant to lower extremity fatigue than athletes, and this may partially explain the lower incidence of ACL injuries in both male and female dancers compared to team athletes. The extensive training in landing technique and daily practice that dancers undergo from a young age may be responsible for the higher levels of endurance.

Comparison of landing biomechanics between male and female dancers and athletes, part 1: Influence of sex on risk of anterior cruciate ligament injury.

BACKGROUND: The incidence of anterior cruciate ligament (ACL) injuries among dancers is much lower than among team sport athletes, and no clear disparity between sexes has been reported in the dance population. Although numerous studies have observed differences in landing biomechanics of the lower extremity between male and female team sport athletes, there is currently little research examining the landing biomechanics of male and female dancers and none comparing athletes to dancers. Comparing the landing biomechanics within these populations may help explain the lower overall ACL injury rates and lack of sex disparity. HYPOTHESIS: The purpose was to compare the effects of sex and group (dancer vs team sport athlete) on single-legged drop-landing biomechanics. The primary hypothesis was that female dancers would perform a drop-landing task without demonstrating typical sex-related risk factors associated with ACL injuries. A secondary hypothesis was that female team sport athletes would display typical ACL risk factors during the same task. STUDY DESIGN: Controlled laboratory study. METHODS: Kinematics and kinetics were recorded as 40 elite modern and ballet dancers (20 men and 20 women) and 40 team sport athletes (20 men and 20 women) performed single-legged drop landings from a 30-cm platform. Joint kinematics and kinetics were compared between groups and sexes with a group-by-sex multivariate analysis of variance (MANOVA) followed by pairwise t tests. RESULTS: Dancers of both sexes and male team sport athletes landed similarly in terms of frontal-plane knee alignment, whereas female team sport athletes landed with a significantly greater peak knee valgus (P = .007). Female dancers were found to have a lower hip adduction torque than those of the other 3 groups (P = .003). Dancers (male and female) exhibited a lower trunk side flexion (P = .002) and lower trunk forward flexion (P = .032) compared with team sport athletes. CONCLUSION: In executing a 30-cm drop landing, female team sport athletes displayed a greater knee valgus than did the other 3 groups. Dancers exhibited better trunk stability than did athletes. CLINICAL RELEVANCE: These biomechanical findings may provide insight into the cause of the epidemiological differences in ACL injuries between dancers and athletes and the lack of a sex disparity within dancers.

A randomized controlled trial comparing the effects of yoga with an active control on ambulatory blood pressure in individuals with prehypertension and stage 1 hypertension.

The purpose of this study was to compare the effects of yoga with an active control (nonaerobic exercise) in individuals with prehypertension and stage 1 hypertension. A randomized clinical trial was performed using two arms: (1) yoga and (2) active control. Primary outcomes were 24-hour day and night ambulatory systolic and diastolic blood pressures. Within-group and between-group analyses were performed using paired t tests and repeated-measures analysis of variance (time × group), respectively. Eighty-four participants enrolled, with 68 participants completing the trial. Within-group analyses found 24-hour diastolic, night diastolic, and mean arterial pressure all significantly reduced in the yoga group (-3.93, -4.7, -4.23 mm Hg, respectively) but no significant within-group changes in the active control group. Direct comparisons of the yoga intervention with the control group found a single blood pressure variable (diastolic night) to be significantly different (P=.038). This study has demonstrated that a yoga intervention can lower blood pressure in patients with mild hypertension. Although this study was not adequately powered to show between-group differences, the size of the yoga-induced blood pressure reduction appears to justify performing a definitive trial of this intervention to test whether it can provide meaningful therapeutic value for the management of hypertension.

Iontophoresis successfully delivers dexamethasone sodium phosphate to dermis as measured by microdialysis.

Despite its widespread and long term use, the effectiveness of iontophoresis to increase the delivery of dexamethasone sodium phosphate (DSP) remains controversial. The goal of this study was to quantitatively compare the DSP concentrations in dermis' dialysates in two delivery scenarios: with and without iontophoresis. Interstitial fluid concentrations were measured by cutaneous microdialysis. Passive and active iontophoresis were applied simultaneously on the skin of the forearm in eight healthy adult participants using each participant as his/her own control. The iontophoresis apparatus and procedures were identical to those used in common clinical practice. Iontophoresis electrodes were loaded with 2 mL of 4.4 mg/mL of preservative-free DSP solution. Electric current (4 mA) was applied for 20 min. Dialysate samples were collected for 2 h and analyzed for DSP and its active metabolite dexamethasone (DXM). Seven out of eight iontophoresis sites contained quantifiable levels of DSP and DXM, whereas none of the samples collected at the passive site contained either form of the drug. In conclusion, this study demonstrates that iontophoresis significantly (p < 0.0001) increases delivery of DSP to the dermis compared with passive delivery of the same, and that microdialysis can be used to monitor DSP delivery and DXM formation in skin.

Breath control during a tiptoe task.

Examination of naturally occurring respiration during postural challenges may increase our understanding of the factors linking respiration to lumbar segmental control. This study determined if the timing and magnitude of inhaled volume changes were related to mechanical events that challenge spinal stability during a tiptoe task. Thirty healthy individuals (15 male) had airflow recorded while they completed a tiptoe task which involved: moving onto tiptoe while reaching toward a hanging target (ascent); grasping and holding the target while maintaining the tiptoe position for 3 s (hold); and then returning to the start position (descent). The rate of airflow and amount of inhaled volume (normalized to vital capacity (%VC)) were identified at 13 different intervals spanning the ascent, hold and descent phase. Using repeated measures analysis of variance, significant main effects were identified for both rate of airflow (p < 0.001) and %VC (p < 0.001). Exploration of these main effects revealed that individuals tended to inspire and increase %VC during the ascent phase, hold their breath and maintain %VC during the hold phase when whole body balance is challenged, and exhale during the descent phase. These findings are congruent with theories suggesting that breath control is linked in predictable ways to potentially improve lumbar spine stiffness when presented with mechanical challenges during functional tasks.

Effectiveness of yoga for hypertension: systematic review and meta-analysis.

Objectives. To systematically review and meta-analyze the effectiveness of yoga for reducing blood pressure in adults with hypertension and to assess the modifying influences of type and length of yoga intervention and type of comparison group. Methods. Academic Search Premier, AltHealthWatch, BIOSIS/Biological Abstracts, CINAHL, Cochrane Library, Embase, MEDLINE, PsycINFO, PsycARTICLES, Natural Standard, and Web of Science databases were screened for controlled studies from 1966 to March 2013. Two authors independently assessed risk of bias using the Cochrane Risk of Bias Tool. Results. All 17 studies included in the review had unclear or high risk of bias. Yoga had a modest but significant effect on systolic blood pressure (SBP) (-4.17 [-6.35, -1.99], P = 0.0002) and diastolic blood pressure (DBP) (-3.62 [-4.92, -1.60], P = 0.0001). Subgroup analyses demonstrated significant reductions in blood pressure for (1) interventions incorporating 3 basic elements of yoga practice (postures, meditation, and breathing) (SBP: -8.17 mmHg [-12.45, -3.89]; DBP: -6.14 mmHg [-9.39, -2.89]) but not for more limited yoga interventions; (2) yoga compared to no treatment (SBP: -7.96 mmHg [-10.65, -5.27]) but not for exercise. Conclusion. Yoga can be preliminarily recommended as an effective intervention for reducing blood pressure. Additional rigorous controlled trials are warranted to further investigate the potential benefits of yoga.

A randomized controlled trial on the effects of yoga on stress reactivity in 6th grade students.

There is an increasing interest in developing school programs that improve the ability of children to cope with psychosocial stress. Yoga may be an appropriate intervention as it has demonstrated improvements in the ability of children to manage psychosocial stress. Yoga is thought to improve the control of reactivity to stress via the regulation of the autonomic nervous system. The current study examined the effects of yoga compared to a physical education class on physiological response (blood pressure (BP) and heart rate (HR)) to behavioral stressor tasks (mental arithmetic and mirror tracing tasks). Data analysis of BP and HR was performed using a 2 × 2 × 4 repeated measures ANOVA (time × group × stressor time points). 30 (17 male) 6th graders participated in the study. Yoga did not provide significant differences in stress reactivity compared to a physical education class (group × time: systolic (F(1,28) = .538, P = .470); diastolic (F(1,28) = .1.061, P = .312); HR (F(1,28) = .401, P = .532)). The lack of significant differences may be due to the yoga intervention failing to focus on stress management and/or the stressor tasks not adequately capturing attenuation of stressor response.

Short-term combined effects of thoracic spine thrust manipulation and cervical spine nonthrust manipulation in individuals with mechanical neck pain: a randomized clinical trial.

STUDY DESIGN: Randomized clinical trial. OBJECTIVE: To investigate the short-term effects of thoracic spine thrust manipulation combined with cervical spine nonthrust manipulation (experimental group) versus cervical spine nonthrust manipulation alone (comparison group) in individuals with mechanical neck pain. BACKGROUND: Research has demonstrated improved outcomes with both nonthrust manipulation directed at the cervical spine and thrust manipulation directed at the thoracic spine in patients with neck pain. Previous studies have not determined if thoracic spine thrust manipulation may increase benefits beyond those provided by cervical nonthrust manipulation alone. METHODS: Sixty-four participants with mechanical neck pain were randomized into 1 of 2 groups, an experimental or comparison group. Both groups received 2 treatment sessions of cervical spine nonthrust manipulation and a home exercise program consisting of active range-of-motion exercises, and the experimental group received additional thoracic spine thrust manipulations. Outcome measures were collected at baseline and at a 1-week follow-up, and included the numeric pain rating scale, the Neck Disability Index, and the global rating of change. RESULTS: Participants in the experimental group demonstrated significantly greater improvements (P<.001) on both the numeric pain rating scale and Neck Disability Index at the 1-week follow-up compared to those in the comparison group. In addition, 31 of 33 (94%) participants in the experimental group, compared to 11 of 31 participants (35%) in the comparison group, indicated a global rating of change score of +4 or higher at the 1-week follow-up, with an associated number needed to treat of 2. CONCLUSION: Individuals with neck pain who received a combination of thoracic spine thrust manipulation and cervical spine nonthrust manipulation plus exercise demonstrated better overall short-term outcomes on the numeric pain rating scale, the Neck Disability Index, and the global rating of change.

The effects of floor incline on lower extremity biomechanics during unilateral landing from a jump in dancers.

Retrospective studies have suggested that dancers performing on inclined ("raked") stages have increased injury risk. One study suggests that biomechanical differences exist between flat and inclined surfaces during bilateral landings; however, no studies have examined whether such differences exist during unilateral landings. In addition, little is known regarding potential gender differences in landing mechanics of dancers. Professional dancers (N = 41; 14 male, 27 female) performed unilateral drop jumps from a 30 cm platform onto flat and inclined surfaces while extremity joint angles and moments were identified and analyzed. There were significant joint angle and moment effects due to the inclined flooring. Women had significantly decreased peak ankle dorsiflexion and hip adduction moment compared with men. Findings of the current study suggest that unilateral landings on inclined stages create measurable changes in lower extremity biomechanical variables. These findings provide a preliminary biomechanical rationale for differences in injury rates found in observational studies of raked stages.

The effects of low back pain on natural breath control during a lowering task.

Preventative and rehabilitative efforts relative to low back pain (LBP) and manual material handling (MMH) are often directed toward proper technique. However, breath control may be an additional factor to consider. Optimizing breath control may provide increased segmental control of the spine through the production of increased intra-abdominal pressure. It has been found that breath control differs during the lifting phase of MMH for individuals with LBP. However, little is known about breath control during the lowering portion even though it accounts for 30% of MMH tasks. In this study, individuals with LBP (n = 32) and aged-matched healthy individuals (n = 30) lowered a crate from a table to the floor four times with the crate empty and four times with the crate loaded at 25% of body weight. The amount of volume in the lungs as a percentage of each individual's vital capacity (VC) was identified at nine points during the lowering task. Individuals with LBP completed the lowering task with significantly more volume in their lungs (45.9% VC) than healthy peers (40.9% VC). Further, with increasing age %VC significantly increased in those with LBP. Moreover, %VC significantly increased in response to the mechanical challenges introduced when lowering a load. These findings support the theoretical link between breath control and lumbar segmental control and provide preliminary evidence supporting rehabilitative efforts which add a focus on breath control for those with LBP.

Assessing and Reporting Dancer Capacities, Risk Factors, and Injuries: Recommendations from the IADMS Standard Measures Consensus Initiative.

This technical report of the Standard Measures Consensus Initiative of the International Association for Dance Medicine and Science (IADMS) describes the results of the committee's multi-year effort to synthesize information regarding the tests and measures used in dance-related research, protocols for reporting injuries, and appropriate use of available technologies to aid in standardizing such matters. Specific recommendations are presented, with accompanying rationales, to facilitate consensus among members of the dance medicine and science community. An Executive Summary of this Technical Report, which contains implementation strategies and appendices, should soon be available on the IADMS website.

The use of stabilization exercises and movement reeducation to manage pain and improve function in a dancer with focal degenerative joint disease of the spine.

Little has been written about rehabilitation of low back pain (LBP) specific to the professional dancer. However, there is a rapidly increasing amount of rehabilitation research related to the care of LBP in the general population that may be applied to the dancer population. The purpose of this case report is to describe the physical therapy management of a 37-year-old female professional dancer with a 5-year history of spinal pain and loss of function in the presence of degenerative joint disease at a single segment (T12-L1). Patient interventions focused on stabilization exercises and movement reeducation. The dancer returned to limited dance performance at 6 weeks. At 5 months she had returned to complete dance function, with pain and functional (Oswestry) levels improved from initial values of 7/10 and 48%, respectively, to 1/10 and 26%.