Validity of the activPAL and Height-Adjusted Curvilinear Cadence-METs Equations in Healthy Adults

ABSTRACT

The activPAL is a widely-used measure of sedentary time but few studies have evaluated its ability to estimate physical activity intensity. This study determined the accuracy of the algorithm used by the activPAL to predict metabolic equivalents (METs) from cadence and a curvilinear cadence-METs equation individualized for height. Thirty-six healthy adults (25 ± 6 years) completed a progressive walking protocol. Stepping cadence was video recorded and METs were determined via indirect calorimetry. Manually-counted cadence was input into the activPAL and curvilinear equations. The internal activPAL equation overpredicted METs at slower cadences (<120 steps/minute) but underpredicted METs at faster cadences (>120 step/minute) (proportional bias, p < .001). Conversely, the curvilinear equation exhibited neither fixed (p = .37) nor proportional bias (p = .07), and a lower absolute MET difference [0.87 ± 0.65 (range:0.0–3.2) vs. 0.56 ± 0.45 (range:0.0–2.7) METs]. The linear activPAL equation poorly estimates METs from stepping cadence but these inaccuracies may be lessened through the use of an individualized curvilinear equation.     

Relational Maintenance and Social Support in the Aftermath of Sudden and Expected Death

Bereavement is a state of grieving after the loss of a loved one. Past research has suggested that bereavement is particularly challenging, both physically and emotionally, in the aftermath of unexpected death. Here, we examine bereavement in which death occurred suddenly, compared to a chronic condition where death was expected, in terms of perceived social support and relational maintenance with the deceased in the form of imagined interactions and social media interactions. Results indicated that individuals experiencing sudden death bereavement were more likely to engage in both postmortem relational maintenance techniques and perceived less social support than individuals in the expected death bereavement group. Results are discussed in terms of previous findings.     

Temporal discrimination of alternate days in rats

The objective was to determine whether rats could learn to time a 48-h interval. Rats (n = 6) were continuously housed in operant chambers in constant darkness. The feeding cycle consisted of unlimited access to food for 6 h, followed by 42 h without access to food (i.e., meals were available on alternate days, contingent on breaking a photobeam in the food trough). Head entries into the trough increased as a function of time prior to the meal; this increase was higher, relative to the increase that occurred at the same time of day on alternate (i.e., nonfood) days. These data suggest that rats discriminated alternate days. Next, two meals were omitted to dissociate mechanisms of a self-sustained endogenous rhythm, interval timing, and alternation. Response rate increased periodically every 24 h, which suggests that the rats anticipated alternate days by discriminating the status of the previous day as a meal or a nonmeal day.     

Proximity-to-goal as a constraint on patterns of behaviour in attacker-defender dyads in team games

The aim of this study was to determine whether spatiotemporal interactions between footballers and the ball in 1 vs. 1 sub-phases are influenced by their proximity to the goal area. Twelve participants (age 15.3 ± 0.5 years) performed as attackers and defenders in 1 vs. 1 dyads across three field positions: (a) attacking the goal, (b) in midfield, and (c) advancing away from the goal area. In each position, the dribbler was required to move beyond an immediate defender with the ball towards the opposition goal. Interactions of attacker-defender dyads were filmed with player and ball displacement trajectories digitized using manual tracking software. One-way repeated measures analysis of variance was used to examine differences in mean defender-to-ball distance after this value had stabilized. Maximum attacker-to-ball distance was also compared as a function of proximity-to-goal. Significant differences were observed for defender-to-ball distance between locations (a) and (c) at the moment when the defender-to-ball distance had stabilized (a: 1.69 ± 0.64 m; c: 1.15 ± 0.59 m; P < 0.05). Findings indicate that proximity-to-goal influenced the performance of players, particularly when attacking or advancing away from goal areas, providing implications for training design in football. In this study, the task constraints of football revealed subtly different player interactions than observed in previous studies of dyadic systems in basketball and rugby union.     

The effect of physical contact on changes in fatigue markers following rugby union field-based training

Repeated physical contact in rugby union is thought to contribute to post-match fatigue; however, no evidence exists on the effect of contact activity during field-based training on fatigue responses. Therefore, the purpose of this study was to examine the effect of contact during training on fatigue markers in rugby union players. Twenty academy rugby union players participated in the cross-over study. The magnitude of change in upper- and lower-body neuromuscular function (NMF), whole blood creatine kinase concentration [CK] and perception of well-being was assessed pre-training (baseline), immediately and 24?h post-training following contact and non-contact, field-based training. Training load was measured using mean heart rate, session rating of perceived exertion (sRPE) and microtechnology (Catapult Optimeye S5). The inclusion of contact during field-based training almost certainly increased mean heart rate (9.7; ±3.9%) and sRPE (42; ±29.2%) and resulted in likely and very likely greater decreases in upper-body NMF (?7.3; ±4.7% versus 2.7; ±5.9%) and perception of well-being (?8.0; ±4.8% versus ?3.4; ±2.2%) 24?h post-training, respectively, and almost certainly greater elevations in [CK] (88.2; ±40.7% versus 3.7; ±8%). The exclusion of contact from field-based training almost certainly increased running intensity (19.8; ±5%) and distance (27.5; ±5.3%), resulting in possibly greater decreases in lower-body NMF (?5.6; ±5.2% versus 2.3; ±2.4%). Practitioners should be aware of the different demands and fatigue responses of contact and non-contact, field-based training and can use this information to appropriately schedule such training in the weekly microcycle.     

Spatial list learning in black-capped chickadees

Learning & Behavior - Black-capped chickadees (Parus atricapillus), a food-storing bird, were presented with three-item lists of unique spatial configurations. Each item consisted of one baited...     

Data archiving for animal cognition research: Report of an NIMH workshop

In July 2001, the National Institute of Mental Health sponsored a workshop titled “Data Archiving for Animal Cognition Research.” Participants included scientists as well as experts in archiving, publishing, policy, and law. As is described in this report, the workshop resulted in a set of conclusions and recommendations concerning (A) the impact of data archiving on research, (B) how to incorporate data archiving into research practice, (C) contents of data archives, (D) technical and archival standards, and (E) organizational, financing, and policy issues. The animal cognition research community is encouraged to begin now to establish archives, deposit data and related materials, and make use of archived materials in new scientific projects.     

Representation of time in time-place learning

Ordinal, interval, and circadian mechanisms of solving a time-place task were tested. Rats searched for food twice in the morning and once in the afternoon (Group AB-C,n=5) or once in the morning and twice in the afternoon (Group A-BC,n=5) in a box with four food troughs. The location of the food depended on the time of day in a 12:12-h light:dark cycle. Acquisition was documented by foodsite inspections at the correct locations prior to food availability. On nonrewarded probes, the time of the middle search (B) was shifted late (for Group AB-C) or early (for Group A-BC). The rats visited Location B at chance, contrary to an ordinal mechanism. When the posttesting meal and light-dark transitions were omitted, the rats visited correct locations with impaired performance but at abovechance levels on nonrewarded probes. The results are consistent with interval and circadian representations of time.     

Tokamaks and turbulence: research ensembles, policy and technoscientific work

A comparative analysis of two fusion energy research facilities is used to examine how the ensemble of research technologies (materials, methods, instruments, techniques, and the like) constructed and used by a group not only connects the group to other researchers and policymakers but also influences the group’s trajectory, performance, and the work of its members. We use a combination of historical, interview, and questionnaire data to describe the two facilities, position them within the field, and examine the working conditions and job satisfaction of their members. We develop the idea of research ensemble, characterize it in comparison with related concepts, explain how it reflects policy priorities and provides a new way for research groups to accumulate advantage and disadvantage. Using multiple regression models, we demonstrate how differences in research ensembles lead to differences in working conditions and job satisfactions. Some implications are proposed for policy in fast-changing, large-scale fields of science and technology.