Influence of Patient Satisfaction of Total Knee Replacement Patients on Stair Negotiation and Walking Biomechanics, Strength, and Balance

Total knee replacement (TKR) patients have shown alterations in lower extremity biomechanics during level ground walking and stair negotiation, strength levels, and balance abilities, however, it is unknown how dissatisfied TKR patients compare to satisfied TKR patients in these activities. Study One examined the lower extremity biomechanics of dissatisfied and satisfied TKR patients during level ground walking. Study Two investigated knee biomechanics during stair ascent and descent activities. Study Three compared isokinetic strength, balance abilities, deep knee flexion abilities, and functional abilities of the dissatisfied patients to the satisfied patients. Study Four performed a logistic regression as a means of examining significant variables in models designed to predict patient satisfaction. Study One found reduced 1st and 2nd peak VGRF, knee flexion ROM, and peak loadingresponse knee extension and abduction moments in the dissatisfied patients compared to healthy controls. First and 2nd peak VGRFs and flexion ROM were reduced in the replaced limb of the dissatisfied patients compared to their non-replaced limb. Study Two showed reduced 2nd peak VGRF and loading-response knee extension moments in the replaced limb of the dissatisfied group compared to their non-replaced limb and to satisfied and healthy groups during stair ascent. 1st peak VGRF and both loading-response and push-off abduction moments showed reduced values in replaced limbs compared to non-replaced limbs for all groups. During stair descent, the dissatisfied group showed reduced loading-response and push-off knee extension moments in their replaced limb compared to their non-replaced limb and the healthy group. The loading-response knee extension and abduction moments were also reduced in the dissatisfied group compared to the satisfied group. Study Three showed reduced peak extension (180°/s) and flexion (60°/s) torque in dissatisfied patients compared to satisfied patients. No balance differences were evident, although an increased percentage of dissatisfied patients were unable to complete the unilateral balance tests. Study Four produced models via the logistic regression analysis which often included peak VGRFs and knee extension moments. Future research should examine the effects of attempting to alter the physical differences between patient satisfaction groups and whether it improves patient satisfaction rates

The efficient IPO market hypothesis: theory and evidence

We derive the optimal underwriting method and the quantitative initial public offering (IPO) pricing rule that this method implies in a market with informational frictions consisting of fully rational banks, issuers, and investors. In an efficient IPO market, an issuer's expected initial return will be determined entirely by the combination of this pricing rule and issuer fundamentals. Applying this rule, we find that we can explain the quantitative magnitude of the principal aspects of the time-series and cross-sectional variation in IPO average initial returns. We conclude that the IPO market is efficient

Effects of Altered Surface Inclinations on Knee Kinematics During Drop Landing

Though it is well known that landing in an excessively inverted and plantar-flexed position commonly causes lateral ankle sprains, this landing motion has not been well studied for its effects on the knee joint. This study examines the effects of landing surface inclinations on knee kinematics during drop landing. Twelve recreational athletes performed five drop landings from an overhead bar with their feet 30 cm above three different surfaces: a flat surface, a 25° inversion surface, and a combined surface of 25° inversion and 25° plantarflexion. Threedimensional kinematic data was collected using a seven-camera Vicon system. Selected knee kinematic variables were assessed using a one-way repeated measure analysis of variance (p \u3c 0.05). Landing on the combined surface resulted in a significantly reduced knee flexion range of motion (ROM, 44.7°) compared to landing on the flat surface (51.3°) and, thus, may likely incur greater knee joint loading due to increased stiffness in the joint. In addition, landing on the combined surface produced a 41% increase in knee abduction ROM compared to the inversion surface. Landing with decreased knee flexion and increased knee abduction ROM may predispose the anterior cruciate ligament to larger strains, thereby increasing the risk of anterior cruciate ligament injury

Frontal Plane Range of Motion Differences in Unilateral and Bilateral Battle Rope Sets: A Pilot Study

Battle rope exercises are commonly used among cross-fitters to build overall muscular strength and cardiorespiratory endurance. Although this training method is physically demanding, no studies have examined the frontal plane movements in the lower extremities when performing battle ropes exercises in their different variations. PURPOSE: The objective of this research was to compare the frontal plane range of motion (ROM) along with the peak joint angles of the ankle, knee, and hip when performing bilateral and unilateral battle ropes exercises. METHODS: Participants with at least six months of resistance training experience performed four sets of bilateral and unilateral battle ropes in a randomized order. The hip, knee, and ankle joint angles were measured using motion-capturing cameras and retroreflective markers placed on the participant’s body. Additionally, the sequence of the angles was measured from the top to bottom motion of the right hand during both unilateral and bilateral activities. RESULTS: The frontal ankle ROM during unilateral measured 2.1 degrees (peak ankle eversion of -5.2 degrees), while during the bilateral battle rope, there was a 1.0 degrees ROM (peak ankle eversion of -3.6 degrees). Additionally, the frontal knee ROM during bilateral battle rope exercises was 4.0 degrees (peak knee adduction of 3.5 degrees), slightly greater than the unilateral battle rope ROM of 3.6 degrees (peak knee adduction of 2.7 degrees). However, in contrast to the ankle and knee, the hip exhibited a significantly greater ROM of 5.9 degrees (peak hip abduction of -17.8 degrees) during unilateral battle rope exercise, as opposed to the 1.8 degrees of ROM (peak hip abduction of -13.7 degrees) during bilateral battle rope exercise. CONCLUSION: This study identified that the hip range of motion was significantly increased when performing unilateral battle rope exercise as opposed to bilateral exercise. The performance of a unilateral battle rope demands a greater side-to-side shift in the frontal plane, requiring the hip joints to accommodate the movements. An increased level of muscular activation in the hip adductors is needed to control the increased range of motion and joint position within the hip joint when performing unilateral battle ropes activities, which involves an increased side to side shifting motion

Effects of Footwear on Deadlift Performance between a Hex Bar and Traditional Bar

The conventional deadlift is mainly performed using a straight (traditional) bar, however variations of the deadlift can use other types of bar such as the hexagonal (hex) bar which shifts the loading to a lateral position on the body. Despite the limited research available, training barefoot has become an uprising training modality that anecdotally suggests improved performance. PURPOSE: To observe the performance differences between a hex bar deadlift (HEX) and the traditional bar deadlift (TRAD) in barefoot and shod conditions. METHODS: On day one, one-repetition maximums (1RM) were assessed for thirteen resistance-trained male and female subjects in only the TRAD condition. At least 72hr later, subjects performed five repetitions in four different conditions (barefoot and shod for both HEX and TRAD) at 70% 1RM. A 2 x 2 (footwear x bar) ANOVA was used to assess differences in barbell vertical displacement (DISP), peak vertical velocity (PV), peak vertical ground reaction force (VGRF), total mechanical work (WORK), and lift time (TIME) during the concentric phase. RESULTS: It was observed that there was no significant interaction between the footwear and bar conditions (p\u3e0.05), however there were significant main effects within the footwear condition (p \u3c 0.001) and the bar condition (p = 0.024). The shod condition was observed to have significantly greater DISP (0.522m vs 0.491m) and WORK (473.5J vs 451.9J) compared to the barefoot condition. The HEX condition was observed to have significantly greater PV (0.847m/s vs 0.784m/s) and WORK (474.0J vs 451.3J) compared to the TRAD condition. CONCLUSION: Despite contrary belief, this study suggests that there is no improvement in deadlift performance when lifting barefoot compared to lifting with shoes. However, the shoe does provide an increase in DISP and WORK performed during the deadlift, which implies an increase in the total mechanical load is applied during the shod condition at a given weight. Deadlifting with a hexagonal bar does elicit greater PV and WORK, which can be taken into consideration when being implemented in training programs as mechanical work is related to the volume of work in a training program

The Effects of Unilateral and Bilateral Battle Rope Exercise on the Lower Extremity Joint Force: A Pilot Study

The battle rope exercise recently has increased its popularity due to cross fit gyms implementing it into the workout programs. Individuals use this workout to strengthen their upper body, however it is unknown how different modalities of using the battle ropes affects the lower extremity joint force required to stabilize the body. PURPOSE: To examine the effects of unilateral and bilateral battle ropes exercises on lower extremity joint force. METHODS: Subjects performed four bilateral battle rope trials and four unilateral battle rope trials. The trials consisted of twenty seconds of continuous activity with three minutes of rest in between during a single visit to the lab. Lower extremity joints were tracked using a Qualisys motion capture system and Bertec force platforms. Joint force data (normalized to body mass) and ground reaction force (reported in Newtons, both in the medial-lateral axis) were analyzed in the down phase of the movement (from peak rope height to the bottom of the motion). RESULTS: There was decreased lateral force in the hip joint during the bilateral exercise for the left hip (0.601BM) and the right hip (0.586BM) compared to the unilateral (0.803BM and 0.614BM, respectively). However, the knee and ankle showed decreased lateral force during the unilateral exercise (0.376BM and 0.200BM for the left and right knee, respectively and 0.829BM and 1.052BM for the left and right ankle respectively) compared to the bilateral exercise (0.569BM and 0.336BM for the left and right knee, respectively and 1.047BM and 1.145BM for the left and right ankle, respectively). The bilateral exercise showed increased medially-directed forces in the right limb (133.4N) and left limb (148.7N) -compared to the unilateral (109.3N and 110.1N, respectively). CONCLUSION: The results show a discrepancy in terms of medial-lateral joint force. The unilateral exercise shows increased lateral stress on the hip joints while the bilateral shows an increased lateral stress on the ankle and knee. During unilateral exercises, the non-active side (side without the moving arm) hip and knee show increased lateral forces while the active-side ankle shows increased lateral forces. Lower extremity joint position should be considered when using these activities due to their impact on joint force experienced in the lower extremities

Model risk of risk models

This paper evaluates the model risk of models used for forecasting systemic and market risk. Model risk, which is the potential for different models to provide inconsistent outcomes, is shown to be increasing with market uncertainty. During calm periods, the underlying risk forecast models produce similar risk readings; hence, model risk is typically negligible. However, the disagreement between the various candidate models increases significantly during market distress, further frustrating the reliability of risk readings. Finally, particular conclusions on the underlying reasons for the high model risk and the implications for practitioners and policy makers are discussed

Can we prove a bank guilty of creating systemic risk? A minority report

Since increasing a bank's capital requirement to improve the stability of the financial system imposes costs upon the bank, a regulator should ideally be able to prove beyond a reasonable doubt that banks classified as systemically risky really do create systemic risk before subjecting them to this capital punishment. Evaluating the performance of two leading systemic risk models, we show that estimation error alone prevents the reliable identification of the most systemically risky banks. We conclude that it will be a considerable challenge to develop a riskometer that is both sound and reliable enough to provide an adequate foundation for macroprudential policy

Model risk of risk models

This paper evaluates the model risk of models used for forecasting systemic and market risk. Model risk, which is the potential for different models to provide inconsistent outcomes, is shown to be increasing with and caused by market uncertainty. During calm periods, the underlying risk forecast models produce similar risk readings, hence, model risk is typically negligible. However, the disagreement between the various candidate models increases significantly during market distress, with a no obvious way to identify which method is the best. Finally, we discuss the main problems in risk forecasting for macro prudential purposes and propose an evaluation criteria for such models

The Effect of Neuropriming and Focus of Attention on Amateur Standing Long Jump Performance

International Journal of Exercise Science 15(1): 1472-1480, 2022. Non-invasive brain stimulation has been prominent in recent neurophysiology research. The use of brain stimulation has not been examined in combination with the focus of attention paradigm, an established motor control tool. Therefore, the purpose of this study was to examine the effects of both brain stimulation and focus of attention on the outcome performance, peak force, lower extremity joint kinematics, and projection angle of a standing long jump. Forty-one participants were assigned to either the brain stimulation group or placebo group via a counterbalance design based on leg length and jump distance. Participants were only accepted if they had not previously trained in the standing long jump. On a second day, participants performed a standing long jump under control, external, and internal attentional foci after having undergone either a single session of brain stimulation or a placebo warm-up. Five total jumps were performed: one baseline jump followed by two for each attentional focus condition. The results indicated that an external focus of attention and control conditions created a reduced projection angle compared to an internal focus of attention and that brain stimulation did not have any effects on the performance of a standing long jump after a single session. There were no changes evident between hip, knee, and ankle joint angles, force production, or jump distance between any of the conditions or groups