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PURPOSE: The purpose of this study was to investigate the age-related changes in diastolic filling parameters in the aging hearts of active C57Bl/6J mice throughout the life span to indicate optimal age periods for improvements in resting diastolic parameters. METHODS: Fourteen C57Bl/6J mice (seven males and seven females) were individually housed at 8 wk of age in cages with a running wheel, magnetic sensor, and digital odometer. Duration, distance, and running velocity were recorded daily. Fourteen additional mice C57Bl/6J mice (seven males and seven females) were placed in individual cages without running wheels at 8 wk of age. Pulsed-wave Doppler transmitral inflow recordings with a SONOS 5500 ultrasound and 15-6L ultrasound probe were used to image the left ventricle every 4 wk throughout the life span. RESULTS: Peak E wave filling velocities were significantly greater by the start of the second quarter of the life span in the mice with access to running wheels (P < 0.0001). Peak E wave velocities improved in both groups during the first half of the life span (P < 0.0001) and declined throughout the second half of the life span (P < 0.0001). Early-to-late (E:A) filling ratio was significantly greater for the physically active mice by the start of the second quarter of the life span (P < 0.0001) and continued throughout most of the remainder of the life span (P < 0.0001). No differences were observed between the two groups of mice with peak A wave filling velocities (P > 0.05). Similar findings were observed when corrected for resting heart rate. CONCLUSIONS: Lifelong physical activity resulted in greater diastolic filling parameters by the second quarter of the life span, highlighting the clinical importance of regular aerobic activity in young adulthood as a mechanism for improved left ventricular performance with aging. [ABSTRACT FROM AUTHOR]

PURPOSE: Older adults are known to gain the benefits of improved cognition, reduced risk of falls, and decreased mortality when participating in regular physical activity. Nearly sixty percent of older adults suggest they are not involved with regular physical activity or exercise, but those who are regularly active participate in different structured and unstructured programming options. Our investigation studied the influence of different physical activity options on perceived quality of life, step counts, and sleep behaviors in the older adult population. METHODS: Forty-five older adult volunteers answered a questionnaire that asked "Do you exercise?" If answered "Yes", then participants were asked "Is it structured (SE-Structured Exercise) or independent (IE-Independent Exercise)?". If answered "No", then participants were asked "Do you lead an active lifestyle (AL-Active Lifestyle) or not (C-Control)?" Nine men and 36 women participated in the current study, with group mean ages (±SD) of SE: 73.9±6.6yrs (n=13), IE: 76.5±6.1yrs (n=13), AL: 79.9±9.6yrs (n=10), C: 69.8±5.8yrs (n=9). Perceived health status and sleep quality were assessed with the SF-36 & PSQI, respectively, while daily energy expenditure and sleep quality were measured through a wrist worn Fitbit Charge HR for seven days. RESULTS: Groups were similar in height and weight (p>0.05), but SE and C were found to be younger (p=0.02) than the IE and AL groups. No group differences were observed for energy expenditure, sleep quality, or sleep efficiency (p>0.05). Pain (p= 0.002) and physical functioning (p=0.01) were lesser in the AL group compared to the remaining groups. Perceived health (p= 0.07) and daily step count (p= 0.07) trended towards group differences but were not statistically significant. CONCLUSIONS: Physical functioning and daily pain were influenced by physical activity programming with older adults, yet daily step counts and energy expenditure was found to not be influenced by type of activity programming with older adults. [ABSTRACT FROM AUTHOR]

PURPOSE: To examine thickness of the anterior talofibular ligament (ATFL) and if that thickness relates to physical activity levels one year after an ankle sprain. METHODS: Twenty college students (8 males and 12 females, age=21.2 ± 2.4yr., mass=80.9±21.6kg, ht=173.3±10.6cm) with an acute LAS and 20 healthy matched controls (8 males and 12 females, age=21.9± 2.8yr., mass=79.1±20.2kg, ht=172.5±9.8cm) participated in the study. ATFL thickness was measured with a LOGIQ Book (GE Healthcare, Waukesha, WI) diagnostic ultrasound. The examiner orientated the probe to view the cross sectional view of the lateral malleolus and the lateral talar articular surface cartilage and the neck of the talus. Measurements of ATFL thickness were made using ImageJ software (National Institutes of Health, Bethesda, MD). Thickness of the ATFL was measured at the midpoint of the ligament between the attachments of the lateral malleolus and talus. The main outcome measures were the thickness of the ATFL (mm) at 3 days post LAS and 1 year post LAS, and physical activity levels as measured by the IPAQ and NASA physical activity scales. RESULTS: There was a significant relationship between ATFL thickness and both the IPAQ and NASA physical activity scales. As ligament thickness increased, "average time spent performing vigorous physical activity" significantly decreased (p=.04, r²=-.86) and "average time spent performing moderate physical activity" (p=.02, r²=-.84) one year after injury. Subjects with a LAS also had a significant relationship with time spent walking (p=.01, r²=-.92), and days per week where they pursued vigorous activity (p=.02, r²=-.81) or moderate activity (p=.04 r²=-.85) one year after their sprain. As ligament thickness increased, overall subjective physical activity scores significantly decreased. CONCLUSIONS: One year after a LAS subjects had a significant relationship with ATFL thickness and activity levels. The changes in ATFL morphology may lead to the decreased physical activity levels due to the feeling of the ankle being unstable. Future research needs to focus on early interventions to ensure proper ligament healing occurs to restore joint function after an ankle sprain. [ABSTRACT FROM AUTHOR]

The article discusses the effect of innate activity level and running wheel access of food consumption in high-active and low-active mice. It states that the balance between food consumption and energy expenditure is important in maintaining the body mass. It also mentions that regardless of body mass, the increase in physical activity by using running wheels or treadmills resulted in the increased food consumption in rodents. Furthermore, it relates that there is a strong positive correlation between daily food intake and daily wheel activity, as measured by average daily distance, duration and speed. It also concluded that during the 13 weeks trial, the high-active and low-active mice tended to balance their energy intake with energy consumption.

Purpose: It is currently unknown whether the age of wheel exposure influences running wheel activity in mice. The purpose of this study was to determine whether the age at which a running wheel was introduced affected running wheel activity for a subsequent 15-wk period. Methods: Twenty female C57B1/6J mice (age 7 wk) were assigned to one of four experimental groups. Group 1 received a running wheel at 7 wk of age. Thereafter, groups 2, 3, and 4 received running wheels at 10, 13, and 16 wk of age, respectively. Daily running wheel activity (duration, distance, and velocity) was recorded from the time of running wheel exposure until 30 wk of age. Results: A repeated-measures MANOVA found significant differences between groups for distance (P = 0.02), duration (P = 0.04), and velocity (P = 0.001) during the 15-wk concurrent running period (age 16-30 wk). Post hoc tests revealed significantly greater distance and duration in group 4 compared with group 2 and significantly greater velocity in group 4 compared with each of the other groups. Significant interactions were found between groups over time for distance (P = 0.01) and duration (P = 0.05). No significant difference between groups was observed for body weight over the 24-wk period (P> 0.05). Conclusion: Although differences were found between groups 2 and 4, these data suggest that the age at which physical activity is introduced has little influence on the subsequent level of physical activity in C57B1/6J mice. However, it appears that introduction of the running wheel at 16 wk of age results in greater within group variance, suggestive of a greater environmental influence on daily running wheel activity. [ABSTRACT FROM AUTHOR]

Ankle sprains are the most common orthopedic pathology experienced during sport and physical activity and often result in chronic ankle instability (CAI). Understanding how to prevent CAI is difficult because of the costs and logistics associated with clinical trials aimed at preventing the heterogeneous symptoms associated with CAI. Thus, a need exists to develop an animal model that presents similar long-term consequences as CAI to assess preclinical data. Thus, the purpose was to determine whether surgically transecting the lateral ligaments of a mouse hind limb results in the development of CAI-like symptoms 12 months after injury. Methods: Thirty male mice (CBA/J) were randomly placed into a SHAM (control), CFL (calcaneofibular ligament; mild ankle sprain), or ATFL/CFL (anterior talofibular ligament/ CFL; severe) ankle sprain group and housed individually. Three days after surgically transecting the respective lateral ligaments, mice were given a solid surface running wheel and daily running wheel measurements were recorded. Outcome measures of balance and gait were obtained before and at 4, 48, 54, and 60 wk after injury. Results: The ATFL/CFL group had significantly more hind foot slips than the CFL and SHAM groups (P < 0.05). The CFL also had more hind foot slips relative to the SHAM group (P < 0.05). The ATFL/CFL group was significantly less physically active relative to the SHAM and CFL groups (P < 0.05). A cut score of 4.75 foot slips had a sensitivity of 0.68 and specificity of 1.00 and indicates that 70% (14/20) of mice with an ankle sprain had developed CAI. Conclusions: The results of this study indicate that an acute ankle sprain in mice can result in the development of CAI-like symptoms 12 months after injury. [ABSTRACT FROM AUTHOR]

Introduction: Ankle sprains remain the most common orthopedic pathology. Conducting long-term studies in humans is difficult and costly, so the long-term consequences of an ankle sprain are not entirely known. Purpose: The objective of this study is to develop and test a mechanical ankle instability model in mice. Methods: Thirty male mice (CBA/2J) were randomly placed into one of three groups: the transected calcaneal fibular ligament (CFL) group, the transected anterior talofibular ligament (ATFL)/CFL group, and a SHAM group. Three days after surgery, all of the mice were individually housed in a cage containing a solid surface running wheel, and daily running wheel measurements were recorded. Before and after surgery, measures of balance and gait were measured on all mice for 4 wk. Results: The mice in the ATFL/CFL group had significantly decreased duration (P = 0.0239), distance (P = 0.013), and speed (P = 0.003) compared with the SHAM group during week 1. During weeks 2 and 3, the ATFL/CFL group had significantly less distance (P = 0.0001) and duration (P = 0.002) compared with the SHAM and CFL-only group. The transection of the lateral ankle ligaments did affect the number of slips experienced during the balance test. The ATFL/CFL group had greater slips at 1 and 4 wk postsurgery (P = 0.05), whereas the CFL-only group had greater slips at 3 d and 1 wk postsurgery (P = 0.05). Relative to the SHAM group, the ATFL/CFL group and CFL-only group had smaller right-stride lengths (involved limb) at 3 d postsurgery (P = 0.05). The ATFL/CFL group also had smaller right-side stride lengths at 1 and 4 wk postsurgery (P = 0.05). Conclusions: The results of this study indicate that a mouse model can be used to induce mechanical instability in the ankle. [ABSTRACT FROM AUTHOR]