Limb bone morphology, bone strength, and cursoriality in lagomorphs.
*Arm Bones/anatomy & histology/physiology; *Lagomorpha/anatomy & histology/physiology; *Leg Bones/anatomy & histology/physiology; *Tensile Strength; Animals; Bone Density/physiology; Mechanical; mechanical advantage; mineralization; Pliability; polar section modulus; robusticity; Running/*physiology; safety factor; Stress; Tomography; X-Ray Computed
The primary aim of this study is to broadly evaluate the relationship between cursoriality (i.e. anatomical and physiological specialization for running) and limb bone morphology in lagomorphs. Relative to most previous studies of cursoriality, our focus on a size-restricted, taxonomically narrow group of mammals permits us to evaluate the degree to which 'cursorial specialization' affects locomotor anatomy independently of broader allometric and phylogenetic trends that might obscure such a relationship. We collected linear morphometrics and muCT data on 737 limb bones covering three lagomorph species that differ in degree of cursoriality: pikas (Ochotona princeps, non-cursorial), jackrabbits (Lepus californicus, highly cursorial), and rabbits (Sylvilagus bachmani, level of cursoriality intermediate between pikas and jackrabbits). We evaluated two hypotheses: cursoriality should be associated with (i) lower limb joint mechanical advantage (i.e. high 'displacement advantage', permitting more cursorial species to cycle their limbs more quickly) and (ii) longer, more gracile limb bones, particularly at the distal segments (as a means of decreasing rotational inertia). As predicted, highly cursorial jackrabbits are typically marked by the lowest mechanical advantage and the longest distal segments, non-cursorial pikas display the highest mechanical advantage and the shortest distal segments, and rabbits generally display intermediate values for these variables. Variation in long bone robusticity followed a proximodistal gradient. Whereas proximal limb bone robusticity declined with cursoriality, distal limb bone robusticity generally remained constant across the three species. The association between long, structurally gracile limb bones and decreased maximal bending strength suggests that the more cursorial lagomorphs compromise proximal limb bone integrity to improve locomotor economy. In contrast, the integrity of distal limb bones is maintained with increasing cursoriality, suggesting that the safety factor takes priority over locomotor economy in those regions of the postcranial skeleton that experience higher loading during locomotion. Overall, these findings support the hypothesis that cursoriality is associated with a common suite of morphological adaptations across a range of body sizes and radiations.
Young Jesse W; Danczak Robert; Russo Gabrielle A; Fellmann Connie D
Journal of anatomy
2014
2014-10
Article information provided for research and reference use only. All rights are retained by the journal listed under publisher and/or the creator(s).
<a href="http://doi.org/10.1111/joa.12220" target="_blank" rel="noreferrer noopener">10.1111/joa.12220</a>
Effectiveness of a group exercise program in a long-term care facility: a randomized pilot trial.
Female; Male; Aged; Sensitivity and Specificity; Prospective Studies; Age Factors; Sex Factors; Analysis of Variance; Patient Compliance; Pliability; Frail Elderly; Nursing Homes; Confidence Intervals; Inpatients; Human; Descriptive Statistics; P-Value; Repeated Measures; Data Analysis Software; Pilot Studies; Clinical Trials; Summated Rating Scaling; Clinical Assessment Tools; Analysis of Covariance; Outcomes (Health Care); Range of Motion; Random Assignment; Treatment Outcomes; Gerontologic Care; Long Term Care; Functional Status; Geriatric Functional Assessment; Crossover Design; Housing for the Elderly; Muscle Strengthening; Recreation; 80 and Over; Group Exercise – In Old Age
Objective:The purpose of this pilot was to determine whether a strength and flexibility program in frail long-term care facility (LTC) residents would result in improved function.Design:A prospective, randomized, controlled, semicrossover trial was designed with participants assigned either to group exercise (EX) or recreational therapy (C). In the EX group, the intervention continued for 1 year. In the C group, recreation continued for 6 months; these controls were then crossed over to the same exercise intervention as the EX group and followed for an additional 6 months. Functional outcomes were measured at baseline and 3, 6, 9, and 12 months for both groups.Setting:A LTC facility, which included both assisted living (AL) and nursing home (NH) residents.Participants:Twenty frail residents (5 from NH, 15 from AL) aged 75 to 99 years at one LTC facility.Intervention:After random group assignment, the EX group met 1 hour three times per week. An exercise physiologist and LTC staff conducted sessions which included seated range of motion (ROM) exercises and strength training using simple equipment such as elastic resistance bands (therabands) and soft weights. The C group met three times per week and participated in activities such as painting during the first 6 months, before crossing over to exercise.Measurements and Methods:Objective measures of physical and cognitive function were obtained at baseline and 3, 6, 9, and 12 months using the timed get-up-and-go test (TUG), Berg balance scale, physical performance test (PPT), and mini-mental status exam (MMSE). Because we were interested in the impact of exercise on multiple endpoints and to protect the type I error rate, a global hypothesis test was used.Results:There was a significant overall impact across the four measures of the exercise intervention (P = 0.013). Exercise benefit as indicated by the difference between exercise and control conditions showed exercise decreased TUG by 18 seconds, which represents an effect size (in standard deviation units) of 0.50, increased PPT scores by 1.3, with effect size = 0.40, increased Berg scores by 4.8, with effect size of 0.32, and increased MMSE by 3.1, with effect size = 0.54. Except for the Berg, 90% confidence intervals on these exercise effects excluded 0.Conclusion:Frail elderly in a LTC facility were able to participate and benefit from a strength training program. The program was delivered with low-cost equipment by an exercise physiologist and LTC staff. The advantage of such a program is that it provides recreational and therapeutic benefits.
Baum EE; Jarjoura D; Polen AE; Faur D; Rutechi G
Journal of the American Medical Directors Association
2003
2003-04-03
Article information provided for research and reference use only. All rights are retained by the journal listed under publisher and/or the creator(s).
<a href="http://doi.org/10.1016/s1525-8610(04)70279-0" target="_blank" rel="noreferrer noopener">10.1016/s1525-8610(04)70279-0</a>