Reliability and validity of field-based measures of leg stiffness and reactive strength index in youths

Abstract

The aim of the study was to assess the reliability of a mobile contact mat in measuring a range of stretch–shortening cycle parameters in young adolescents. Additionally, vertical leg stiffness using contact mat data was validated against a criterion method using force–time data. The reliability study involved 18 youths completing a habituation and three separate test sessions, while 20 youths completed a single test session for the validity study. Participants completed three trials of a squat jump, countermovement jump, and maximal hopping test and a single trial of repeated sub-maximal hopping at 2.0 Hz and 2.5 Hz. All tests were performed on the contact mat. Reliability statistics included repeated-measures analysis of variance, intraclass correlation coefficient, and coefficient of variation (CV), while the correlation coefficient (r) and typical error of estimate (TEE) were reported for the validity study. Squat jump height was the most reliable measure (CV = 8.64%), while leg stiffness during sub-maximal hopping, and reactive strength index produced moderate reliability (CV = 10.17–13.93% and 13.98% respectively). Measures of leg stiffness obtained from contact mat data during sub-maximal hopping were in agreement with the criterion measure (r = 0.92–0.95; TEE = 6.5–7.5%), but not during maximal hopping (r = 0.59; TEE = 41.9%). The contact mat was deemed a valid tool for measuring stretch–shortening cycle ability in sub-maximal but not maximal hopping. Although reliability of performance was generally moderate, the tests offer a replicable assessment method for use with paediatric populations.     

Effects of playing surface on physiological responses and performance variables in a controlled football simulation

Abstract

In spite of the increased acceptance of artificial turf in football, few studies have investigated if matches are altered by the type of surface used and no research has compared physiological responses to football activity on artificial and natural surfaces. In the present study, participants performed a football match simulation on high-quality artificial and natural surfaces. Neither mean heart rate (171 ± 9 beats · min^?1 vs. 171 ± 9 beats · min^?1; P > 0.05) nor blood lactate (4.8 ± 1.6 mM vs. 5.3 ± 1.8 mM; P > 0.05) differed between the artificial and natural surface, respectively. Measures of sprint, jumping and agility performance declined through the match simulation but surface type did not affect the decrease in performance. For example, the fatigue index of repeated sprints did not differ (P > 0.05) between the artificial, (6.9 ± 2.1%) and natural surface (7.4 ± 2.4%). The ability to turn after sprinting was affected by surface type but this difference was dependent on the type of turn. Although there were small differences in the ability to perform certain movements between artificial and natural surfaces, the results suggest that fatigue and physiological responses to football activity do not differ markedly between surface-type using the high-quality pitches of the present study.     

Influence of vitamin D mushroom powder supplementation on exercise-induced muscle damage in vitamin D insufficient high school athletes

Abstract

Incidence of vitamin D deficiency is increasing worldwide. The purpose of this study was to determine if supplementation with vitamin D₂ from Portobello mushroom powder would enhance skeletal muscle function and attenuate exercise-induced muscle damage in low vitamin D status high school athletes. Participants were randomised to Portobello mushroom powder (600 IU/d vitamin D₂) or placebo for 6 weeks. Participants then completed a 1.5-h exercise session designed to induce skeletal muscle damage. Blood samples and measures of skeletal muscle function were taken pre-supplementation, post-supplementation/pre-exercise and post-exercise. Six weeks supplementation with vitamin D₂ increased serum 25(OH)D₂ by 9.9-fold and decreased serum 25(OH)D₃ by 28%. Changes in skeletal muscle function and circulating markers of skeletal muscle damage did not differ between groups. In conclusion, 600 IU/d vitamin D₂ increased 25(OH)D₂ with a concomitant decrease in 25(OD)D₃, with no effect on muscular function or exercise-induced muscle damage in high school athletes.     

Health-inclusive higher education: listening to students with disabilities or chronic illnesses

This paper reports on a small-scale project undertaken with tertiary students who identified as having an impairment either at enrolment or by registering with the university's Disability Support Unit (DSU). The aim of the study was to explore with these students ways in which the university was currently meeting their academic support needs and the ways in which these needs might be better met. Consistent with the definition of disability within the Australian Disability Discrimination Act, it became apparent that a significant number of students who identified with that definition, or sought help from disability services, also presented with needs arising from chronic illness. The majority of participants cited an emotional or psychological illness, rather than a physical, intellectual or sensory one, as a possible precursor to difficulties in engagement with the university. We conclude by considering whether commonly used institutional categories are apposite to an understanding of the ways in which students perceive themselves and, importantly, their engagement with the university and success within it.     

Effects of ICT group work on interactions and social acceptance of a primary pupil with Asperger's Syndrome

The aim of this study was to ascertain whether collaborative group work on a computer, facilitated by an adult, could provide a means for a primary schoolboy with Asperger's Syndrome (AS)—moderately‐highly affected in all areas of the “triad of impairments”—to develop appropriate task‐related interactions with his peers. Data were gathered before, during, and after group work sessions. A combination of interviews and questionnaires established background data and concerns of parent and teachers. Sociometric testing of classmates was used to determine social acceptance and friendship grouping among the child's immediate peer group. During the adult‐facilitated ICT sessions an interaction process schedule (IPS) was used to record interactions of the three children involved. The results indicate moderate improvements in the child's ability to interact with his peers, both in social and task‐related contexts, as well as a raised social profile among his classmates in general. Although this was a discrete setting, the findings are encouraging and this strategy may be replicated in schools to support mainstream inclusion for children with AS.     

General education in research universities: Training programs for teaching assistants

Suggestions for general education reforms have advocated smaller classes and greater participation by senior faculty. This is not feasible given the reward structure and extensive use of teaching assistants at research universities. Realistic reform efforts must account for the reward structure and focus on training programs for teaching assistants.She obtained her Ph.D. (1987) in Higher Education Administration, and her M.S. (1982) in Counseling and Human Development, both from the University of Iowa.     

The effects of the Webster-Stratton parenting program on maltreating families: fostering strengths

OBJECTIVE: This study examined the effects of the Webster-Stratton parenting program on the parenting skills of maltreating mothers and on the autonomy of their children (3-8 years). METHOD: A randomized controlled trial was used. Twenty-six maltreating families were randomly assigned to one of two conditions: the 16-hour weekly intervention group, or the 4-month wait list control group. Pre- and post-intervention independent assessments included a 2-hour home visit involving videotaped mother-child interactions during two prescribed, 10-minute play activities. RESULTS: Compared to the control group, treatment mothers demonstrated significant improvement in involvement and marginally significant improvement in autonomy-support, but no improvement in structure. Treatment group children showed no significant improvement in autonomy when compared to control group children. CONCLUSIONS: This parenting program proved effective with maltreating parents. The lack of demonstrated effect on children may reflect the need for a larger and more sustained treatment dose and/or the need to include parent-child interaction opportunities in the program. At the same time, while treatment gains were limited to the parent, the high treatment adherence rate (92% attended six or more of the eight program sessions) and low attrition rate (n=1) indicate that the treatment gains may hold potential for more thorough examination.     

Using LOGO with Infant School Children

Abstract The recent introduction of micro‐computers into schools is opening up many new avenues for developmental psychologists interested in studying how children learn. Of particular interest at present are approaches in which children program computers themselves, using languages such as LOGO and PROLOG. This paper describes a study in which a simplified version of LOGO was introduced to a group of six‐year‐olds in a severely deprived area of Edinburgh. The children used a special touch‐sensitive keyboard (Concept Keyboard) to control the movements of a floor‐crawling robot called a Turtle. The sessions with the Turtle were marked by high levels of concentration, collaborative problem‐solving and the use of mathematical language. Pre‐ and post‐tests on the British Ability Scales revealed statistically significant gains on the sub‐scales concerned with number and shape: these gains, however, were found only in the boys.     

Change in Student Perceptions of Course and Instructor Following Curriculum Change

Ongoing curriculum change in higher education is essential to enhance student learning and better prepare them for the job‐market. However, research shows that faculty are reluctant to implement such changes because students generally react adversely thereby negating any potential benefits, and moreover, sanction faculty through lower evaluations and future enrollment. Yet, understanding of the effect of curriculum changes on students’ course and instructor perceptions is limited. In this article we attempt to fill this gap. Drawing on two empirical findings—students’ motivation to attend college becoming increasingly extrinsic since the 1960s and their inability to recognize, ex ante, the value‐added by a curriculum change—and the norm life‐cycle theory, we argue that any effort‐increasing or grade‐threatening change is viewed as non‐normative and will lead to an adverse student reaction. However, this adverse reaction will dissipate over time once a critical mass of students is convinced of the merits of the new curriculum. We find support for our hypotheses by analyzing change in student perceptions following curriculum changes at a U.S. University. In addition, we also find that once the adverse reaction dissipates, students’ perceptions of the new curriculum become more positive than the old curriculum, only to be reversed once the revised curriculum is accepted as the new norm.