1 81 90 A MATHEMATICAL MODEL OF EFFECTS ON SPECIFIC JOINTS DURING PRACTICE OF THE SUN SALUTATION--A SEQUENCE OF YOGA POSTURES. THE 'SUN SALUTATION' CONSISTS OF A SEQUENCE OF TEN YOGA POSTURES, EACH POSTURE COUNTERACTING THE PRECEDING ONE PRODUCING A BALANCE BETWEEN FLEXION AND EXTENSION, PERFORMED WITH SYNCHRONIZED BREATHING AND AEROBIC ACTIVITY. AS THIS SEQUENCE IS OFTEN PERFORMED AND RECOMMENDED BY MANY YOGA PRACTITIONERS, THERE IS A NEED FOR THE DEVELOPMENT OF A BIOMECHANICAL MODEL TO SUPPORT ITS REPORTED CLINICAL BENEFITS. THIS REQUIRES A DETAILED KNOWLEDGE OF THE NATURE OF THE FORCES AND MOMENTS AT THE VARIOUS JOINTS INVOLVED. A SIMPLE MATHEMATICAL MODEL BASED ON RIGID BODY MECHANICS IS DEVELOPED FOR EACH OF THE SUN SALUTATION POSTURES. DYNAMIC MOMENTS WITH HIGH MAGNITUDES AND RATES, APPLIED WITH UNUSUAL DISTRIBUTION PATTERNS, OPTIMAL FOR OSTEOGENESIS, ARE FOUND TO OCCUR. ALSO, THE JOINTS ARE SUBJECTED TO SUBMAXIMAL LOADINGS THUS ENSURING THAT NONE OF THE JOINTS ARE OVERSTRESSED. 2011 2 1290 28 GROUND REACTION FORCES GENERATED BY TWENTY-EIGHT HATHA YOGA POSTURES. ADHERENTS CLAIM MANY BENEFITS FROM THE PRACTICE OF YOGA, INCLUDING PROMOTION OF BONE HEALTH AND PREVENTION OF OSTEOPOROSIS. HOWEVER, NO KNOWN STUDIES HAVE INVESTIGATED WHETHER YOGA ENHANCES BONE MINERAL DENSITY. FURTHERMORE, NONE HAVE ESTIMATED REACTION FORCES APPLIED BY YOGA PRACTITIONERS. THE PURPOSE OF THIS STUDY WAS TO COLLECT GROUND REACTION FORCE (GRF) DATA ON A VARIETY OF HATHA YOGA POSTURES THAT WOULD COMMONLY BE PRACTICED IN FITNESS CENTERS OR PRIVATE STUDIOS. TWELVE FEMALE AND EIGHT MALE VOLUNTEERS PERFORMED A SEQUENCE OF 28 HATHA YOGA POSTURES WHILE GRF DATA WERE COLLECTED WITH AN AMTI STRAIN-GAUGE FORCE PLATFORM. THE SEQUENCE WAS REPEATED SIX TIMES BY EACH STUDY SUBJECT. FOUR DEPENDENT VARIABLES WERE STUDIED: PEAK VERTICAL GRF, MEAN VERTICAL GRF, PEAK RESULTANT GRF, AND MEAN RESULTANT GRF. UNIVARIATE ANALYSIS WAS USED TO IDENTIFY MEAN VALUES AND STANDARD DEVIATIONS FOR THE DEPENDENT VARIABLES. PEAK VERTICAL AND RESULTANT VALUES OF EACH POSTURE WERE SIMILAR FOR ALL SUBJECTS, AND STANDARD DEVIATIONS WERE SMALL. SIMILARLY, MEAN VERTICAL AND RESULTANT VALUES WERE SIMILAR FOR ALL SUBJECTS. THIS 28 POSTURE YOGA SEQUENCE PRODUCED LOW IMPACT GRF APPLIED TO UPPER AND LOWER EXTREMITIES. FURTHER RESEARCH IS WARRANTED TO DETERMINE WHETHER THESE FORCES ARE SUFFICIENT TO PROMOTE OSTEOGENESIS OR MAINTAIN CURRENT BONE HEALTH IN YOGA PRACTITIONERS. 2012 3 1813 15 PROGRESSION OF GLAUCOMA ASSOCIATED WITH THE SIRSASANA (HEADSTAND) YOGA POSTURE. THIS ARTICLE REPORTS A CASE OF PROGRESSIVE GLAUCOMATOUS OPTIC NEUROPATHY AND VISUAL FIELD LOSS THAT OCCURRED IN A PATIENT WHO PRACTICED THE SIRSASANA (HEADSTAND) YOGA POSTURE ON A DAILY BASIS FOR MANY YEARS. VISUAL FIELD ANALYSIS WAS PERFORMED THROUGH STANDARD AUTOMATED PERIMETRY. INTRAOCULAR PRESSURE (IOP) WAS MEASURED THROUGH PNEUMOTONOMETRY IN THE SITTING POSITION AND IN THE HEAD-DOWN POSITION. STEREO-OPTIC DISC PHOTOGRAPHS WERE OBTAINED. IOP INCREASED SIGNIFICANTLY IN THE HEAD-DOWN POSITION. OPTIC DISC EVALUATION REVEALED A NEW DISC HEMORRHAGE IN THE LEFT EYE. VISUAL FIELD ANALYSIS OVER A PERIOD OF 2 Y SHOWED PROGRESSION OF A SUPERIOR ARCUATE DEFECT IN THE LEFT EYE. TRANSIENT INCREASES IN IOP ASSOCIATED WITH THE YOGA HEADSTAND POSTURE MAY LEAD TO PROGRESSIVE GLAUCOMATOUS OPTIC NERVE DAMAGE AND VISUAL FIELD LOSS. 2006 4 1348 17 IDENTIFYING YOGA-BASED KNEE STRENGTHENING EXERCISES USING THE KNEE ADDUCTION MOMENT. BACKGROUND: THIS STUDY AIMED TO COMPARE MUSCLE ACTIVATIONS, CO-CONTRACTION INDICES, AND THE KNEE ADDUCTION MOMENT BETWEEN STATIC STANDING YOGA POSTURES TO IDENTIFY APPROPRIATE EXERCISES FOR KNEE OSTEOARTHRITIS. METHODS: HEALTHY YOUNG WOMEN (24.4 (5.4) YEARS, 23.1 (3.7) KG/M(2)) PARTICIPATED. PRIMARY OUTCOME VARIABLES WERE ELECTROMYOGRAPHIC ACTIVATIONS OF THE VASTUS LATERALIS, RECTUS FEMORIS, VASTUS MEDIALIS, BICEPS FEMORIS, AND SEMITENDINOSUS; CO-CONTRACTION BETWEEN THE BICEPS FEMORIS AND RECTUS FEMORIS, AND VASTUS LATERALIS AND VASTUS MEDIALIS; AND KNEE ADDUCTION MOMENTS OF BOTH LEGS DURING SIX STATIC, STANDING YOGA POSTURES (TWO SQUATTING POSTURES, TWO LUNGING POSTURES, A HAMSTRING STRETCH, AND A SINGLE-LEG BALANCE POSTURE). A TWO-FACTOR REPEATED MEASURES ANALYSIS OF VARIANCE WAS USED TO IDENTIFY DIFFERENCES IN MUSCLE AMPLITUDES, CO-CONTRACTIONS, AND KNEE ADDUCTION MOMENT BETWEEN POSTURES AND LEGS. FINDINGS: QUADRICEPS ACTIVATIONS WERE HIGHEST DURING SQUAT AND LUNGE POSTURES (P