The effect of stroboscopic visual disruption on static stability measures in anterior cruciate ligament reconstructed individuals.

BACKGROUND: Those who undergo ACL reconstruction are at an increased risk of suffering a second ACL injury. A suggested rationale for the increased injury risk is sensory reweighting to the visual system to compensate for a lack of somatosensory information from the knee. Understanding this proposed visual reliance may help clinicians improve return to sport outcomes and reduce the risk of a subsequent ACL injury. METHODS: Thirteen ACL reconstructed individuals and thirteen matched controls completed two common static postural control assessments under three different visual conditions; eyes open, low visual disruption, and high visual disruption. Center of pressure data was collected for 30 s using force plates. Static postural stability was evaluated using the following: 1) root mean square distance, 2) mean velocity, 3) sway area, and 4) mean frequency. FINDINGS: No significant interactions between group and vision were observed. Significant differences between groups were observed for mean frequency in the double-limb stance (p < .05). Additionally, significant differences were observed for visual conditions in both double-limb (mean velocity; p < .05) and single-limb stances (root mean square distance, mean velocity, sway area, and mean frequency; p < .05). INTERPRETATION: The findings of the current study suggest that ACL reconstructed individuals, who are at least two years removed from surgery, do not rely on visual information to a greater extent than controls during static postural stability assessments. Stroboscopic glasses may be a cost-effective alternative for rehabilitation purposes compared to the traditional binary eyes open vs. eyes closed methods.

Strides to Achieve a Stable Symmetry Index During Running.

CONTEXT: The quality of running mechanics is often characterized by limb pattern symmetry and used to support clinical decisions throughout the rehabilitation of lower-extremity injuries. It is valuable to ensure that gait analyses provide stable measures while not asking an individual to complete an excessive number of running strides. The present study aimed to determine the minimum number of strides required to establish a stable mean symmetry index (SMSI) of discrete-level measures of spatiotemporal parameters, joint kinematics, and joint kinetics. Further, the study aimed to determine if differences occurred between random and consecutive strides for directional and absolute symmetry indices. DESIGN: Descriptive laboratory study. METHODS: A sequential average was used to determine how many strides were required to achieve a SMSI within a 60-second trial. Multiple 2-factor repeated-measure analysis of variances were used to determine if differences between bins of strides and symmetry calculations were significantly different. RESULTS: A median SMSI was achieved in 15 strides for all biomechanical variables. There were no significant differences (P > .05) found between consecutive and random bins of 15 strides within a 60-second trial. Although there were significant differences between symmetry calculation values for most variables (P < .05), there appeared to be no systematic difference between the numbers of strides required for stable symmetry for either index. CONCLUSIONS: As 15 strides were sufficient to achieve a SMSI during running, a continued emphasis should be placed on the number of strides collected when examining interlimb symmetry.

Do Athletes With a Reconstructed Anterior Cruciate Ligament Respond Differently Than Controls to Visual Challenges When Dynamic Postural Stability is Assessed?

Individuals returning to sport after anterior cruciate ligament reconstruction (ACLR) are at an increased risk of sustaining a subsequent ACL injury. It is suspected that increased reliance on visual information to maintain stability may factor into this increased risk. The connection between visual reliance and ACLR is not well understood during dynamic tasks. Examination of the proposed visual reliance may help improve returning to sport standards and reduce subsequent ACL injury risk. A total of 12 ACLR individuals and 12 age- and sex-matched controls completed several trials of a normalized dynamic hop task on both limbs under 3 different visual conditions (eyes open, low visual disruption, and high visual disruption). Stroboscopic eyewear were worn by each participant to disrupt vision during testing. Ground reaction force data were collected during landing. Dynamic postural stability was assessed using 2 separate calculations: dynamic postural stability index and time to stability. No significant statistical interactions or group differences were observed. The stroboscopic eyewear did increase the medial-lateral stability index from the eyes open to the low visual disruption condition (P < .05). These findings suggest that ACLR individuals do not rely on visual information more than controls during a dynamic hop task.

Exercise training improves postural steadiness in cancer survivors undergoing chemotherapy.

BACKGROUND: Cancer and cancer treatments negatively affect somatosensory, vestibular, and visual inputs that regulate postural stability and balance, increasing the risk of falling. Exercise training has been shown to mitigate other negative side effects of cancer treatments, such as reducing peripheral neuropathy. RESEARCH QUESTION: How does 12 weeks of supervised exercise training influence postural stability in cancer survivors who receive chemotherapy? METHODS: Postural stability of cancer survivors (n = 25; mass = 79.0 ± 22.6 kg; height = 1.66 ± 0.08 m; age = 61 ± 10 years) receiving chemotherapy was assessed prior to and following a 12-week individualized exercise training program by quantifying changes in center of pressure data. A series of 2-factor (pre/post x condition) analysis of variance with repeated measures were used to identify differences between conditions and pre- and post- training program on time and frequency domain measures. RESULTS: Mediolateral root mean square excursion (p = 0.040; es = 0.20) and resultant mean frequency (p = 0.044; es = 0.29) of the center of pressure trajectory were found to be significantly different between pre- and post-training program. Further, participants dealt better with perturbations after completing the training program by reducing mediolateral root mean square excursion and 95 % confidence ellipse when visual stimulus was removed. SIGNIFICANCE: Supervised exercise training in cancer patients undergoing chemotherapy improves postural stability in the mediolateral direction. Given that mediolateral movement of the center of pressure has previously been associated with fallers in other populations, exercise training during cancer treatments may be beneficial.

The Influence of Ankle Braces on Functional Performance Tests and Ankle Joint Range of Motion.

CONTEXT: The lateral ankle sprain is one of the most common lower-extremity injuries in sports. Previous research has found that some prophylactic ankle supports reduce the risk of recurrent ankle sprains and provide extra support to the joint. However, there is a continued concern that these supports may negatively influence performance. OBJECTIVE: To determine if wearing an ankle brace influences athlete performance and ankle kinematics during functional performance tests. DESIGN: Repeated measures. SETTING: University gymnasium. OTHER PARTICIPANTS: Male and female recreational or competitive athletes (n = 20). INTERVENTION: Participants performed 3 trials of a standing long jump, vertical jump, 40-yard sprint, and T-drill under each of the following 3 conditions: wearing traditional lace-up brace (brace 1), modified lace-up brace (brace 2), and no-brace. MAIN OUTCOME MEASURES: A 2-dimensional motion capture camera was used to measure ankle range of motion (ROM) in the sagittal plane during the vertical and standing long jumps and in the frontal plane during the cutting phase of the T-drill. Performance of each test and ankle ROM were compared between each of the braced conditions. RESULTS: Ankle braces did not influence performance in speed or agility functional performance tests (P > .05). Ankle braces negatively affected performance of the standing long jump (P = .01) and vertical jump (P = .01). There was no significant difference between brace or no-brace conditions in ankle inversion ROM during the T-drill (P > .05). Both brace conditions restricted ROM in the sagittal plane during the vertical and standing long jumps (P < .05). CONCLUSIONS: Braced conditions restricted sagittal plane ROM during the vertical jump and long jump. This decrease in ROM explains the decline in functional performance also seen during these tests.

Artificial interfaces ("AI") in surgery: historic development, current status and program implementation in the public health sector.

The past two decades have seen considerable advances in the application of artificial interfaces (AI) in surgery. Several have been developed including AESOP (Automated Endoscopic System for Optimal Positioning), Zeus and the Da Vinci Surgical System (DVSS). Whilst each has advantages DVSS is being used increasingly across multiple surgical specialities. These developments generate many challenges in an era where the emphasis is increasingly on safer and cost-effective surgery. Whilst the role of DVSS is firmly established in urologic and gynaecologic surgery, the role of DVSS in gastrointestinal surgery is evolving. Recent data indicate that it is at least as oncologically effective, whilst providing numerous benefits (e.g. reduced conversion and complication rates) over traditional laparoscopic approaches. The increasing adoption of AI/DVSS worldwide places institutes and health sectors under increasing pressure to adopt and develop such programs. This article provides (1) an update on the current status of AI in surgery in general and in colorectal surgery and (2) an appraisal of the cost implications of the establishment and implementation of AI/DVSS-based provisions in the public health sector. The numerous challenges faced generate many opportunities in the implementation of present and future surgical technologies.