Relationship between hip and core strength and frontal plane alignment during a single leg squat.

OBJECTIVE: The purpose of this study was to examine the relationship between frontal plane kinematics of the single leg squat and strength of the trunk and hip in females. PARTICIPANTS: Forty healthy females participated in this study. METHODS: An isometric "make" test using a dynamometer was used to assess peak force normalized to body weight for hip abduction, hip extension, hip external rotation, and a sidelying plank test. Two-dimensional software was used to analyze the frontal plane projection angle (FPPA) and pelvic angle during a single leg squat to 60°. RESULTS: All 4 strength factors were significantly correlated with the FPPA, ranging from r = 0.396 to r = 0.466. During multiple regression analysis, hip abduction strength was the greatest predictor of the variation in FPPA at r(2) = 0.22, p = 0.002. Thus, hip abduction strength accounted for 22% of the variation in the FPPA during the single leg squat. The only strength factor demonstrating a significant correlation with the pelvic angle was hip extension strength (r = 0.550, p < 0.001). CONCLUSION: Clinicians should consider the role of the hip abductors, hip external rotators, hip extensors and core musculature on the impact on the FPPA during a single squat, with focus on the hip abductors.

The functional movement screening (fms)™: an inter-rater reliability study between raters of varied experience.

BACKGROUND: Previous researchers have reported on the reliability of the scoring of the FMS™ movement screens. Those authors have reported good to excellent inter-rater reliability between paired raters of similar experience level (either novice or expert), but no comparisons of inter-rater reliability exist between a novice and an expert. PURPOSE: The purpose of this investigation was to examine the inter-rater reliability of the scoring of the FMS™ between trained novices and an expert rater using video records. METHODS: Twenty healthy college students participated. Each participant performed the series of seven functional movement screens. Four raters (three novices and one expert) independently scored the seven FMS™ tests by watching video recordings of the movements.. RESULTS: The mean total FMS™ score for all subjects was 14.6 ± 1.9, and was not significantly different between raters (p = 0.136). For the individual tests, half of them had perfect agreement, while the other half ranged from slight to moderate agreement (33-66%). CONCLUSION: Total FMS™ scores were similar among the raters, and the inter-rater reliability for a majority of the individual tests had as strong agreement despite the various level of experience of the raters scoring the FMS™ tests. CLINICAL RELEVANCE: Although there was mostly moderate to perfect agreement among raters, the level of experience of the rater scoring the FMS™ should be considered, as it appears that the expert rater was more critical than novice raters in the interpretation of the scoring criteria. LEVEL OF EVIDENCE: Level 3.

Correlation of Titleist Performance Institute (TPI) level 1 movement screens and golf swing faults.

Although some research in the past has examined how physical limitations in strength or flexibility affect a golfer's performance, the performance outcome most measured was driving distance. Currently, there are no data that have examined the relationship between selected strength and flexibility variables and golf swing faults. The purpose of this study was to examine the relationship between Titleist Performance Institute (TPI) level 1 movement screen variables and 14 common golf swing faults. Thirty-six male and female golfers (mean age, 25.4 ± 9.9 years; height, 175.9 ± 16.2 cm; mass, 76.2 ± 14.6 kg; handicap, 14.2 ± 10.4) participated. Twelve physical tests of strength, flexibility, and balance were assessed using the TPI level 1 golf fitness screening tool. Golfers then hit 4 golf shots (with a 5-iron) while being videoed, and those were then analyzed for 14 different golf swing faults (using V1Pro software). Three significant associations between a physical limitation and a particular golf swing fault were found: toe touch and early hip extension (p = 0.015), bridge on right side with both early hip extension (p = 0.050), and loss of posture (p = 0.028). In addition, an odds ratio showed that when a golfer could not overhead deep squat or single leg balance on left side, they were 2-3 times more likely to exhibit a early hip extension, loss of posture, or slide during the golf swing, as compared with those who could perform a correct overhead deep squat. Based on our findings, it is important for the golf fitness professional to particularly address a golfer's core strength, balance, and hamstring flexibility to help avoid common golf swing faults, which affect a golfer's ball striking ability and ultimately their performance.

Weight-bearing hip rotation range of motion in female golfers.

BACKGROUND: Many sports involve movements during which the lower extremity functions as a closed kinetic chain, requiring weight-bearing (WB) range of motion (ROM). Assessment of the capacity for internal and external rotation motion at the hip is typically performed with the individual in a prone, supine, or seated position. Such measurements represent ROM in a non-weight bearing (NWB) position, and, as a result, may not appropriately assess the capacity of the joint to meet the demands of the athlete's sport. To date, no research exists which documents WB hip ROM in golfers relative to the ROM demands of the golf swing or the symmetry of weight-bearing hip rotation ROM in female golfers. OBJECTIVES: Weight-bearing hip rotation ROM was measured in female golfers and compared to the actual hip rotation ROM that occurred during a full golf swing. METHODS: Fifteen right-handed, female collegiate golfers participated in the study. The WB hip rotation ROM was measured during three different stance conditions and during full golf swings using a custom-built testing device. These actions were captured using a 3-D motion analysis system. RESULTS: The golfers WB ROM was symmetrical for external rotation and internal rotation, p = 0.648 and p = 0.078, respectively. During the backswing, the golfers used approximately 20-25% of their available WB right internal rotation, and 50-75% of their available WB left external rotation. For the downswing, the golfers used approximately 34-37% of their available WB right external rotation and 84-131% of their available WB left internal rotation. The golfers used significantly more external and internal hip rotation ROM on the left (lead) hip during both phases of the full golf swing (p < 0.001), demonstrating an asymmetrical movement pattern. DISCUSSION: In general, golfers did not exceed the measured WB ROM limits during the golf swing but did demonstrate decreased WB internal rotation on the lead hip. CONCLUSION: Clinicians need to pay special attention to functional (WB) hip rotation ROM in female golfers in order to assess injury risk related to the rotational hip asymmetry present during the golf swing.

Hip rotational velocities during the full golf swing.

Since labral pathology in professional golfers has been reported, and such pathology has been associated with internal/external hip rotation, quantifying the rotational velocity of the hips during the golf swing may be helpful in understanding the mechanism involved in labral injury. Thus, the purpose of this study was to determine the peak internal/external rotational velocities of the thigh relative to the pelvis during the golf swing. Fifteen female, collegiate golfers participated in the study. Data were acquired through high-speed three dimensional (3-D) videography using a multi-segment bilateral marker set to define the segments, while the subjects completed multiple repetitions of a drive. The results indicated that the lead hip peak internal rotational velocity was significantly greater than that of the trail hip external rotational velocity (p = 0.003). It appears that the lead hip of a golfer experiences much higher rotational velocities during the downswing than that of the trail hip. In other structures, such as the shoulder, an increased risk of soft tissue injury has been associated with high levels of rotational velocity. This may indicate that, in golfers, the lead hip may be more susceptible to injury such as labral tears than that of the trailing hip. Key pointsLead hip of golfer experiences significantly higher rotational velocities than the trail hip.Golfers may be more susceptible to injuries on the lead hip.Clubhead velocities were consistent with elite female golfers.