Repeated-measures Crossover Design Research Articles

Thermoregulation is not impaired in breast cancer survivors during moderate-intensity exercise performed in warm and hot environments.

This study aimed to assess how female breast cancer survivors (BCS) respond physiologically, hematologically, and perceptually to exercise under heat stress compared to females with no history of breast cancer (CON). Twenty‐one females (9 BCS and 12 CON [age; 54 ± 7 years, stature; 167 ± 6 cm, body mass; 68.1 ± 7.62 kg, and body fat; 30.9 ± 3.8%]) completed a warm (25℃, 50% relative humidity, RH) and hot (35℃, 50%RH) trial in a repeated‐measures crossover design. Trials consisted of 30 min of rest, 30 min of walking at 4 metabolic equivalents, and a 6‐minute walk test (6MWT). Physiological measurements (core temperature (T re), skin temperature (T skin), heart rate (HR), and sweat analysis) and perceptual rating scales (ratings of perceived exertion, thermal sensation [whole body and localized], and thermal comfort) were taken at 5‐ and 10‐min intervals throughout, respectively. Venous blood samples were taken before and after to assess; IL‐6, IL‐10, CRP, IFN‐γ, and TGF‐β1. All physiological markers were higher during the 35 versus 25℃ trial; T re (~0.25℃, p = 0.002), T skin (~3.8℃, p < 0.001), HR (~12 beats·min−1, p = 0.023), and whole‐body sweat rate (~0.4 L·hr−1, p < 0.001), with no difference observed between groups in either condition (p > 0.05). Both groups covered a greater 6MWT distance in 25 versus 35℃ (by ~200 m; p = 0.003). Nevertheless, the control group covered more distance than BCS, regardless of environmental temperature (by ~400 m, p = 0.03). Thermoregulation was not disadvantaged in BCS compared to controls during moderate‐intensity exercise under heat stress. However, self‐paced exercise performance was reduced for BCS regardless of environmental temperature.

Short-Term Fasting and Ingestion of Caloric Drinks Affect Heartbeat-Evoked Potentials and Autonomic Nervous System Activity in Males

Central nervous systems receive and process information from the internal and external environment to maintain homeostasis. This includes interoceptive awareness of the organism’s nutritional state. Whenever food supply is required, feelings of hunger initiate the search for and the consumption of appropriate amounts of nutrients. How this is physiologically regulated in humans has been subjected to research into interoceptive awareness of body states during fasting and food consumption. However, there is no research on the distinct effects of carbohydrate or protein intake on interoception. Therefore, we aimed to investigate the impact of fasting and consumption of standardized carbohydrate and protein shakes on interoception in a repeated-measures cross-over design in a sample of 37 healthy, normal weight males. As a physiological correlate of interoception, we measured heartbeat-evoked potentials (HEPs), which are suggested to reflect the cortical representation of cardiac signals, during eight-minutes resting state EEG-recordings. After a 16-hour fasting period, the HEP amplitudes were lower over right central and parietal electrodes and increased after ingestion of the nutritional shake. Exploratory analyses indicated that the difference between fasting and satiety was more prominent at carbohydrate compared protein testing days. Correlation analyses with heart rate variability (HRV) suggested that high cardiac sympathetic activity is related to lower HEP amplitudes. Furthermore, cardiac sympathetic activity and stress indices decreased from before to after the intervention, whereas HRV increased. Together, this study shows for the first time that fasting and the intake of a nutritional shake affects cardiac measures of autonomic nervous system functioning and the neural correlates of cardiac interoception. These findings could be relevant for diets and psychosomatic disorders, including eating disorders.

Older drivers’ experience with automated vehicle technology

Adults 65 years of age and older make up a fifth of the US population, prefer driving as their primary mode of transportation, and may derive health and safety benefits from using automated vehicles (AVs), assuming they accept and adopt these technologies. This study used a repeated measures crossover design, with random allocation of 104 older drivers who were exposed to an automated shuttle and a driving simulator in automated mode (Level 4, Society of Automotive Engineers). Participants completed pre- and post-exposure surveys, to report their perceptions via the Automated Vehicle User Perception Survey. Researchers utilized a two-way mixed ANOVA to analyze time effect, group effect, and time by group interaction effects. No group effects were evident, but older drivers’ perceptions of safety, trust and perceived usefulness of AV technology increased after being exposed to the AV technology. The group by time interaction effects indicated significant perceptions pertaining to intention to use, trust, perceived usefulness, control/driving efficacy, and safety. This study contributes to the body of knowledge regarding the determinants of older adult AV technology acceptance practices. Yet, it is recommended that future studies build on this work to identify the role of different regulatory systems, levels of technology, geographical contexts, and policies–that may influence older drivers’ perceptions of AV technology, before targeted policy and/or practice recommendations can be made. • Older drivers' perceived safety increased after exposure to the automated shuttle and simulator. • Older drivers' trust increased after exposure to the automated shuttle. • Older drivers' perceived usefulness increased after exposure to the simulator in automated mode. • Automated vehicles may provide health and safety benefits if older drivers accept it.

Bilateral regional extracranial blood flow regulation to hypoxia and unilateral duplex ultrasound measurement error

What is the central question of this study? Is blood flow regulation to hypoxia different between the internal carotid arteries (ICAs) and vertebral arteries (VAs), and what is the measurement error in unilateral extracranial artery assessments compared to bilateral? What is the main finding and its importance? ICA and VA blood flow regulation to hypoxia is comparable when factoring for vessel type and vessel side. Compared to bilateral assessment, vessels assessed unilaterally had individual measurement errors of up to 37%. Assessing the vessel with the larger resting blood flow, not the left or right vessel, reduces unilateral measurement error. Whether blood flow regulation to hypoxia is similar between left and right internal carotid arteries (ICAs) and vertebral arteries (VAs) is unclear. Extracranial blood flow is regularly calculated by doubling a unilateral assessment; however, lateral artery differences may lead to measurement error. This study aimed to determine extracranial blood flow regulation to hypoxia when factoring for vessel type (ICAs or VAs) and vessel side (left or right) effects, and to investigate unilateral assessment measurement error compared to bilateral assessment. In a repeated-measures crossover design, extracranial arteries of 44 participants were assessed bilaterally by duplex ultrasound during 90min of normoxic and poikilocapnic hypoxic (12.0% fraction of inspired oxygen) conditions. Linear mixed model analyses revealed no Condition × Vessel Type × Vessel Side interaction for blood flow, vessel diameter and flow velocity (all P>0.05) indicating left and right ICA and VA blood flow regulation to hypoxia was similar. Bilateral hypoxic reactivity was comparable (ICAs, 1.4 (1.0) vs. VAs, 1.7 (1.1) Δ%·Δ -1 ; P=0.12). Compared to bilateral assessment, unilateral mean measurement error of the relative blood flow response to hypoxia was up to 5%, but individual errors reached 37% and were greatest in ICAs and VAs with the smaller resting blood flow due to a ratio-scaling problem. In conclusion, left and right ICA and VA regulation to hypoxia is comparable when factoring for vessel type and vessel side. Assessing the ICA and VA vessels with the larger resting blood flow, not the left or right vessel, reduces unilateral measurement error.

Foregut Exclusion Enhances Incretin and Insulin Secretion After Roux-en-Y Gastric Bypass in Adults With Type 2 Diabetes.

Patients with type 2 diabetes experience resolution of hyperglycemia within days after Roux-en-Y gastric bypass (RYGB) surgery. This is attributed, in part, to enhanced secretion of hindgut factors following exclusion of the gastric remnant and proximal intestine during surgery. However, evidence of the mechanisms of remission remain limited due to the challenges of metabolic evaluation during the early postoperative period. The purpose of this investigation was to determine the role of foregut exclusion in the resolution of type 2 diabetes after RYGB. Patients with type 2 diabetes (n = 15) undergoing RYGB had a gastrostomy tube (G-tube) placed in their gastric remnant at time of surgery. Patients were randomized to receive a mixed meal tolerance test via oral or G-tube feeding immediately prior to and 2 weeks after surgery in a repeated measures crossover design. Plasma glucose, insulin, C-peptide, incretin responses, and indices of meal-stimulated insulin secretion and sensitivity were determined. Body weight, fat mass, fasting glucose and insulin, and circulating lipids were significantly decreased 2 weeks after surgery. The glycemic response to feeding was reduced as a function of total area under the curve but not after adjustment for the reduction in fasting glucose. Oral feeding significantly enhanced insulin and incretin secretion after RYGB, which was entirely ablated by G-tube feeding. Foregut exclusion accounts for the rise in incretin and insulin secretion but may not fully explain the early improvements in glucose metabolism after RYGB surgery.

Outcomes of a training video on the shared reading behaviours of caregivers and children

Despite evidence supporting the implementation of book sharing interventions, few studies have examined the value of providing caregiver training in these contexts. This study draws on the quantitative findings of a larger project that employed a non-randomized comparison group crossover repeated measures design as part of a mixed research approach. The goal of the study was to determine the outcome of a caregiver training video on the book sharing behaviours of 40 caregiver–child dyads in an impoverished peri-urban settlement in South Africa. Children in this study were aged 3 to 6 years of age. Caregivers included older siblings, parents, and other relatives. Findings revealed a significant improvement in caregiver shared reading behaviours in both experimental and comparison groups after viewing the caregiver training video, both within and between groups. The significant change in the shared reading behaviours of the caregivers and children, coupled with the positive impact observed in the children and the cost-effective nature of the intervention, suggest that training videos may constitute an effective intervention medium with the potential to promote children’s literacy as a population-based intervention in majority world settings.

Loudness Dependence of Auditory-evoked Potentials, a Marker of Central Serotonergic Activity, is Affected by Fasting and Selective Uptake of Food.

Serotonin is an important neuromodulator involved in many physiological processes including mood and satiety. In the brain, serotonin is manufactured from tryptophan, as serotonin itself cannot cross the blood-brain barrier. Previous research has shown that blood-tryptophan levels increase upon ingestion of carbohydrates and decrease upon protein consumption. How this translates into serotonin availability is as yet under-researched. Therefore, we examined the effect of fasting versus consuming carbohydrates or protein on central serotonergic activity using a repeated-measures crossover design in a sample of 37 healthy men. The loudness dependence of auditory-evoked potentials (LDAEP) serves as a noninvasive method to study central serotonergic activity. Blood-glucose levels and mood changes were also monitored before and after the nutritional intervention. The intervention had a significant nutrition-specific effect on LDAEP and blood-glucose levels. A significant difference emerged between the fasting condition and satiety, with LDAEP being lower during satiety, irrespective of the type of food. Thus, this indicator of serotonergic activity increased after food consumption, which was further related to mood improvement. Moreover, the LDAEP differed between the 2 measurements only for the carbohydrate testing day, suggesting that LDAEP can be selectively modulated by the type of nutrition consumed. Our data further indicate a high intraindividual stability of LDAEP, as the electrophysiological signals were very similar in the fasting condition across the 2 testing days. Together, these findings demonstrate that the LDAEP can serve as a biological marker for central serotonergic activity, while at the same time being sensitive to nutritional changes.

The effect of dairy products and non-dairy snacks on food intake, subjective appetite and cortisol levels in children: a randomized control study.

Dairy snacks are available in various physical forms and their consumption is linked to improved metabolic health. The objective of this study was to determine the effect of dairy snacks of different physical forms on short-term food intake (FI), subjective appetite, and the stress hormone, cortisol, in children. Following a repeated-measures crossover design, 40 children aged 9-14 years randomly consumed 1 of 5 isoenergetic (180 kcal) snacks per study session. These snacks included solid (potato chips, cookies, and cheese), semi-solid (Greek yogurt), and fluid (2% fat milk) snacks. FI was measured 120 min after snack consumption. Subjective appetite was measured at 0 (immediately before the snack), 15, 30, 45, 60, 90, and 120 min. Salivary cortisol (n = 18) was measured after the Greek yogurt and cookie snacks at 0, 30, 60, 90, and 120 min. FI did not differ between snacks (P = 0.15). The Greek yogurt (P < 0.0001) and cheese (P = 0.0009) snacks reduced average appetite compared with the 2% fat milk snack. Salivary cortisol levels were not affected by snack (P = 0.84). This study demonstrates that dairy snacks are as effective as other popular snacks at influencing subsequent FI. However, solid and semi-solid dairy snacks are more effective at repressing subjective appetite than a fluid dairy snack. Registered at ClinicalTrials.gov (NCT02484625). Novelty: Milk, Greek yogurt and cheese have a similar effect on short-term food intake in children as popular potato chips and cookie snacks. Solid, semi-solid and liquid snacks have a similar effect on short-term food intake in children.

A Comparison of the Effect of 20- and 40-Min Session Durations of External Counterpulsation on Neuromuscular Function, Cortisol and Comfort in Physically Active Young Men

External Counterpulsation (ECP) is a well-established treatment for coronary disease, with interest growing in the potential to act as a sports recovery modality or pre-performance strategy. This pilot study compared the effects of different ECP durations upon neuromuscular function (NF), cortisol and subjective perceptions in a rested state. Eleven physically active male volunteers received two ECP treatments (Renew Sport, Singapore) of differing duration (20-min and 40-min) in a randomised, repeated measures crossover design. Testing occurred pre-ECP, post-ECP, and 24-h post-ECP. NF testing comprised counter-movement jumps (CMJs) and 6-s sprint cycling. Saliva samples were analysed for cortisol. Rate of Perceived Exertion (RPE, 6 to 20) and Bipolar Comfort Scales (− 10 to 10) quantified participants’ experiences, and ECP duration preference was examined. Repeated measures ANOVA and effect size (ES: Cohen’s d) analysed NF and cortisol results. Paired t-tests analysed RPE and comfort ratings. ECP demonstrated no effect, neither positive nor negative, upon NF outcome measures in both groups. A trend of reduced salivary cortisol levels across both groups following ECP was observed (P = 0.066). No RPE difference existed between groups. 20-min of ECP was rated as significantly more comfortable than 40-min (P < 0.05) and participants predominantly identified the 20-min ECP session as “more acceptable”. These results indicate that there were no effects for either duration upon the defined outcome measures, and thus, in these circumstances, no differences between the two durations were observed with respect to effects upon NF and salivary cortisol. The use of ECP warrants further investigation for potential benefits to performance before it can be proposed as an effective preparatory modality.

Effect of Acute Interset Foot Cooling on Lower Limb Strength Training Workout.

The authors investigated the effect of foot cooling (FC) between sets in a leg press pyramid workout with resistance-trained participants. A total of 12 resistance-trained men (age = 21.8 [0.6]y; training experience = 1.7 [1]y) performed a pyramid workout, including 4 sets of 85% to 90% 1-repetition maximum leg press exercise to exhaustion with interset FC or noncooling in a repeated-measures crossover design separated by 5days. The authors immersed the participants' feet in 10°C water for 2.5minutes between sets. Two-way repeated-measures analysis of variance revealed that FC elicited significantly higher repetitions and electromyography (EMG) values of the vastus lateralis (simple main effect of condition) than did noncooling (P < .05) in the second (repetitions: 11 [3.5] vs 7.75 [3.2]; EMG: 63.4% [19.4%] vs 54.5% [18.4%]), third (repetitions: 8.9 [3.2] vs 6.4 [2.1]; EMG: 71.5% [17.4%] vs 60.6% [19.4%]), and fourth (repetitions: 7.5 [2.7] vs 5.1 [2.2]; EMG: 75.2% [19.6%] vs 59.3% [23.5%]) sets. The authors also detected a simple main effect of set in the FC and noncooling conditions on repetitions (P < .05) and in the FC condition on the vastus lateralis EMG values. Although the authors observed no time × trial interactions for the rating of perceived exertion, the authors observed main effects on the sets (7.7-9.6 vs 7.9-9.3, P < .05). Interset FC provides an ergogenic effect on a leg press pyramid workout and may offset fatigue, as indicated by higher repetitions and EMG response, without increasing perceived exertion.

Postoperative pain and edema control following different protocols of preemptive analgesia in the surgical removal of impacted third molars: A triple-blind parallel randomized placebo-controlled clinical trial

This randomized controlled clinical trial aimed to evaluate the preemptive effects of acetaminophen, ibuprofen, ketoprofen, nimesulide or dexamethasone on postoperative pain and edema in the surgical removal of impacted third molars.Participants underwent bilateral surgeries at 2 different times and were randomly given the test drug or placebo (split-mouth). Postoperative pain, edema and rescue medication were evaluated at different times. Study power was >80% for the observed effect size in the crossover repeated measures design. Differences between test drug and placebo were the response variable. Generalized Estimation Equation models were adjusted for each outcome.Sample comprised 5 groups (n = 20 each). Ibuprofen and nimesulide showed higher overall effects on pain scores over time, with no differences between them (p = 0.557). Acetaminophen showed significantly lower overall effects in edema control over time, when compared to other test drugs, that showed similar effects. Lower quantity of rescue medication were also observed for ibuprofen and nimesulide, with no differences between them (p = 0.999). Ibuprofen and nimesulide showed beneficial overall preemptive effects. Hence, in the decision-making process for preemptive analgesia in impacted third molar surgeries, ibuprofen and nimesulide should be considered on a case-by-case basis as the drugs of choice.

Influence of Fluid Delivery Schedule and Composition on Fluid Balance, Physiologic Strain, and Substrate Use in the Heat

Wildfire suppression is characterized by high total energy expenditure and water turnover rates. Hydration position stands outline hourly fluid intake rates. However, dose interval remains ambiguous. We aimed to determine the effects of microdosing and bolus-dosing water and microdosing and bolus-dosing carbohydrate-electrolyte solutions on fluid balance, heat stress (physiologic strain index [PSI]), and carbohydrate oxidation during extended thermal exercise. In a repeated-measures cross-over design, subjects completed four 120-min treadmill trials (1.3 m·s-1, 5% grade, 33°C, 30% relative humidity) wearing a US Forest Service wildland firefighter uniform and a 15-kg pack. Fluid delivery approximated losses calculated from a pre-experiment familiarization trial, providing 22 doses·h-1 or 1 dose·h-1 (46±11, 1005±245 mL·dose-1). Body weight (pre- and postexercise) and urine volume (pre-, during, and postexercise) were recorded. Heart rate, rectal temperature, skin temperature, and steady-state expired air samples were recorded throughout exercise. Statistical significance (P<0.05) was determined via repeated-measures analysis of variance. Total body weight loss (n=11, -0.6±0.3 kg, P>0.05) and cumulative urine output (n=11, 677±440 mL, P>0.05) were not different across trials. The micro-dosed carbohydrate-electrolyte trial sweat rate was lower than that of the bolus-dosed carbohydrate-electrolyte, bolus-dosed water, and microdosed water trials (n=11, 0.8±0.2, 0.9±0.2, 0.9±0.2, 0.9±0.2 L·h-1, respectively; P<0.05). PSI was lower at 60 than 120 min (n=12, 3.6±0.7 and 4.5±0.9, respectively; P<0.05), with no differences across trials. The carbohydrate-electrolyte trial's carbohydrate oxidation was higher than water trial's (n=12, 1.5±0.3 and 0.8±0.2 g·min-1, respectively; P<0.05), with no dosing style differences. Equal-volume diverse fluid delivery schedules did not affect fluid balance, PSI, or carbohydrate oxidation during extended thermal work.

The effect of altering routine husbandry factors on sleep duration and memory consolidation in the horse

Sleep is a critically important behaviour for all mammals due to its fundamental role within homeostatic/circadian systems and memory consolidation. As a large and vigilant prey species that is highly sensitive to stimuli at night, the horse sleeps less than other mammalian species. For this reason, the domestic environment has the potential to greatly affect the duration and quality of equine sleep. This study aimed to determine the effect of environmental factors on equine sleep stages, and whether this would influence cognitive performance during a spatial memory task. Ten riding school horses (mixed breed/ height/ sex; average age 14.9 + 2.4 years) were randomly assigned to two groups (n = 5) within a five-week crossover repeated measures design experiment. Each group experienced a combination of one of two light conditions (lights on = Treatment; lights off = Control), and one of two bedding depth treatments (15 cm bed = control; 5 cm bed = treatment) for six days. Duration of sleep stage behaviours (standing Non-Rapid Eye Movement [NREM]), sternal NREM, sternal Rapid Eye Movement [REM] and lateral REM) were measured continuously using CCTV infrared cameras. For the spatial memory task, latency, number of correct responses, and differences between these parameters during training and testing days were measured. A repeated measures general linear model assessed the effects of treatment conditions on duration of sleep stage, and changes in sleep stage over time (bedding and light set as within-subject factors). Wilcoxon Signed-Rank and paired t-tests determined differences in memory task parameters between treatments. Comparing Treatment Bedding with Control Bedding conditions, horses spent on average significantly less time in lateral REM (0.34 ± 0.12 versus 0.46 ± 0.13 h; p = 0.032) and sternal NREM (0.64 ± 0.10 versus 0.80 ± 0.12 h; p = 0.007), and significantly more time in standing NREM (3.69 ± 0.76 versus 3.17 ± 0.77; p = 0.024). Only sternal REM was significantly affected during the Treatment Light condition compared to control conditions (0.53 ± 0.07 versus 0.67 ± 0.11; p = 0.031). Interactions between day and treatment were apparent for specific sleep stage behaviours indicative of acclimatisation. No significant effects (p > 0.05) of Treatment Light or Bedding conditions were detected for performance during the spatial memory test. Overall, horses exposed to sub-optimal conditions tended to display significantly less time in recumbent sleep stages (NREM and REM) and increased time in a standing NREM stage. The impact of reduced sleep on equine cognition requires further study.

Brief Compassion-Focused Imagery Dampens Physiological Pain Responses

ObjectivesAffiliative processes are postulated to improve pain coping. Comparatively, compassion-focused imagery (CFI) also stimulates affiliate affect systems with a burgeoning behavioural, cognitive and physiological evidence base. Thus, the purpose of the present research was to investigate if engaging in brief CFI could improve pain coping.MethodsUtilising a randomised repeated measures crossover design, 37 participants were subjected to experimental pain (cold pressor) following counter-balanced engagement with CFI or control imagery, 1 week apart. Salivary alpha-amylase (sAA) and questionnaire measures of emotional responding were taken: at baseline, following introduction to the imagery condition (anticipation), and immediately after the cold pressor pain task (actual).ResultsParticipants exhibited increases in sAA levels in response to pain following control imagery but, no such changes were observed following CFI (i.e. there was a significant time-by-condition interaction). Pain tolerance (the length of time participants immersed their hands in the cold pressor) did not differ by imagery condition. However, sAA responses to actual pain predicted decreased pain tolerance in the CFI condition. Additionally, anticipatory sAA response predicted increased pain tolerance across both conditions. None of the emotional measures of well-being differed by imagery condition, nor by condition over time.ConclusionsThese data demonstrate that using CFI can curtail a physiological stress response to pain, as indicated by increases in sAA in the control imagery condition only, following pain; pain tolerance was not influenced by CFI. Compassion-based approaches may therefore help people cope with the stress associated with pain.

Affective responses to high-intensity interval training with continuous and respite music

ABSTRACT Music has been shown to enhance affective responses to continuous exercise, but the most effective application of music during interval exercise is poorly understood. This study examined two contrasting applications of music designed to assuage the decline in pleasure often experienced during high-intensity interval training (HIIT). In a repeated measures crossover design, 18 recreationally active participants (10 men and 8 women; M age = 25.1 ± 5.1 years; M BMI = 23.08 ± 2.01 kg/m 2; M VO2max = 38.82 ± 10.73 ml/kg/min) completed three HIIT sessions (10 x 60 s efforts at 100% Wmax, separated by 75 s recovery) on a cycle ergometer. Participants completed two experimental conditions: respite music (applied only during the recovery periods), continuous music (applied throughout the entire HIIT session); and a no-music control condition. Results indicated that music did not influence affective valence during the work bouts or recovery periods of the HIIT sessions (ps >.05), but that listening to music continuously elicited greater post-task enjoyment (p =.032, d = 0.66) and remembered pleasure (p =.044, d = 0.5). This study is the first to investigate the application of music during a practical HIIT protocol and to compare the effects of respite versus continuous music during interval exercise.

Effects of Exercise on Sport Concussion Assessment Tool-Third Edition Performance in Women.

The purpose of this study was to examine the influence of a brief exercise protocol on Sport Concussion Assessment Tool-Third Edition (SCAT3) performance in amateur women athletes. Cross-over repeated-measures design. Off-season, uninjured community amateur athletes. We examined 87 amateur women athlete volunteers (age = 29.9, SD = 6.9 years). Participants were assessed using the SCAT3 under 2 conditions: at rest and after a 5-minute physical exertion protocol, completed in a counterbalanced order. Participants' performance on the various components of the SCAT3 under the 2 conditions: at rest and after a 5-minute physical exertion protocol. No significant differences were detected between at-rest and postexercise conditions for the balance, orientation, or cognitive components of the SCAT3. There were no significant differences in the proportion of participants who endorsed specific symptoms at rest compared with the postexercise condition (P > 0.05). However, women athletes who rated their exertion after exercise as "hard" or greater (Borg scale rating 13-20) reported significantly greater blurred vision (M = 0.25, SD = 0.62 vs M = 0.00, SD = 0.00; P = 0.006) and fatigue/low energy (M = 1.38, SD = 1.17 vs M = 0.66, SD = 0.91; P = 0.002) symptoms after exercise than those who rated their exertion as "light" or lower (Borg scale rating 6-12). In this study of women athletes, a brief bout of exercise did not seem to adversely affect SCAT3 performance and had only small effects on self-reported symptoms. There were differences in symptom reporting, however, in the subgroup of women who rated their exertion levels as "hard" or greater; they reported more blurred vision and fatigue/low energy.

Game format alters the physiological and activity demands encountered during small-sided football games in recreational players

BackgroundConditioning in the form of football small-sided games (SSG) is being increasingly utilized as a health-promoting and performance-enhancing activity. ObjectiveThe aim of this study was to quantify and compare the physiological responses and activity demands encountered during 3-a-side, 4-a-side, and 5-a-side football SSG in recreational players. MethodHeart rate, blood lactate (BLa), rating of perceived exertion (RPE) and activity demands were measured across 2 × 20-min football sessions played on a 40 × 20-m pitch in 12 recreationally active college students. Data were collected over a period of two weeks using a repeated-measures crossover design. ResultsMean heart rate was higher (moderate) during 5-a-side than 4-a-side (p = 0.02) and 3-a-side SSG (p < 0.001). BLa tended to be higher (small) in 3-a-side compared to 4-a-side (p = 0.12) and 5-a-side SSG (p = 0.46). The total distance covered was lower (large) during 5-a-side than 4-a-side SSG (p = 0.02), while the total number of accelerations (p = 0.01) and decelerations (p = 0.02) were higher (large) during 5-a-side than 4-a-side SSG. ConclusionThese data suggest: 1) 5-a-side SSG require a greater intermittent workload and exacerbated HR responses; 2) 4-a-side SSG require more sustained activity (distance); and 3) 3-a-side SSG result in higher BLa compared to other SSG formats. The observed intermittent workload and exacerbated HR response in 5-a-side SSG were likely due to greater turnover rates with more frequent interceptions. Sustained activity in 4-a-side SSG might be underpinned by format-specific structures permitting optimal team work, while isolated guarding of players in 3-a-side SSG may have exacerbated BLa responses.

Effect of Sand on Landing Knee Valgus During Single-Leg Land and Drop Jump Tasks: Possible Implications for ACL Injury Prevention and Rehabilitation.

Despite significant emphasis on anterior cruciate ligament injury prevention, injury rates continue to rise and reinjury is common. Interventions to reduce injury have included resistance, balance, and jump training elements. The use of sand-based jump training has been postulated as an effective treatment. However, evidence on landing mechanics is limited. To determine potential differences in landing strategies and subsequent landing knee valgus when performing single-leg landing (SLL) and drop jump (DJ) tasks onto sand and land, and to compare between both male and female populations. A randomized repeated-measures crossover design. University laboratory. Thirty-one participants (20 males and 11 females) from a university population. All participants completed DJ and SLL tasks on both sand and land surfaces. Two-dimensional frontal plane projection angle (FPPA) of knee valgus was measured in both the DJ and SLL tasks (right and left) for both sand and land conditions. FPPA was lower (moderate to large effect) for SLL in sand compared with land in both legs (left: 4.3° [2.8°]; right: 4.1° [3.8°]) for females. However, effects were unclear (left: -0.7° [2.2°]) and trivial for males (right: -1.1° [1.9°]). FPPA differences for males and females performing DJ were unclear; thus, more data is required. Differences in FPPA (land vs sand) with respect to grouping (sex) for both SLL left (4.9° [3.0°]) and right (5.1° [4.0°]) were very likely higher (small)/possibly moderate for females compared with males. The effects of sand on FPPA during DJ tasks in males and females are unclear, and further data is required. However, the moderate to large reductions in FPPA in females during SLL tasks suggest that sand may provide a safer alternative to firm ground for female athletes in anterior cruciate ligament injury prevention and rehabilitation programs, which involve a SLL component.

Translation and Validation of the Hospital for Special Surgery Pediatric Functional Activity Brief Scale for French Paediatric Populations.

Purpose: Physical activity level is a prognostic variable for patients with injuries. Self-report questionnaires exist to obtain these measures; however, they are not accessible to all populations because of language barriers. Therefore, the purpose of this study was to translate and validate the Hospital for Special Surgery Pediatric Functional Activity Brief Scale (HSS Pedi-FABS) for francophones. Method: We translated the HSS Pedi-FABS using the forward-reverse translation approach and validated it among bilingual adults and an expert panel before administering it to a paediatric population. A repeated-measures crossover design was used: forty-three middle school students, aged 13.1 (SD 0.75) years, were randomly administered either the English or the French questionnaire. Two days later, all participants completed the other version. The translated questionnaire was assessed for its convergent validity (Spearman's r correlation coefficients [rs ]), internal consistency (Cronbach's α), and reliability (standard error of measurement [SEM]). Results: All assessments had a significance level of p<0.001 with an excellent Spearman's r correlation coefficient between the participants' total scores on the translated questionnaires (rs =0.911). The overall scores for the questionnaire and the individual items of the questionnaire revealed excellent internal consistency (α=0.868) and reliability (SEM=0.334). Conclusions: The validated and reliable translated questionnaire can be used by researchers and clinicians to assess physical activity levels in French paediatric populations.

The effect of unilateral hand contractions on psychophysiological activity during motor performance: Evidence of verbal-analytical engagement

ObjectivesConscious engagement in movement control can influence motor performance. In most cases, the left hemisphere of the brain plays an important role in verbal-analytical processing and reasoning, so changes in the balance of hemispheric activation may influence conscious engagement in movement. Evidence suggests that unilateral hand contractions influence hemispheric activation, but no study has investigated whether there is an associated effect of hand contractions on verbal-analytical processing during motor performance. This study utilized psychophysiological (and behavioural) measures to examine whether pre-performance unilateral hand contraction protocols change verbal-analytical engagement during motor performance. DesignA repeated measures crossover design was employed. MethodsTwenty-eight participants completed three hand contraction protocols in a randomised order: left-, right- and no-hand contractions. Electroencephalography (EEG) measures of hemispheric asymmetry were computed during hand contractions. A golf putting task was conducted after each protocol. EEG connectivity between sites overlying the left verbal-analytical temporal region (T7) and the motor planning region (Fz) was computed for the 3 sec prior to movement initiation. Additionally, electrocardiography (ECG) and electromyography (EMG) signals were analysed 6 sec prior to movement initiation until 6 sec after. Golf putting performance (distance from the target) and putter swing kinematics were measured. ResultsContralateral hemisphere activity was revealed for the left-hand and right-hand contraction conditions. During motor planning, the left-hand contraction protocol led to significantly lower T7-Fz connectivity, and the right-hand contraction protocol led to significantly higher T7-Fz connectivity than the other conditions. EMG, ECG and kinematic measures did not differ as a function of condition. Importantly, T7-Fz connectivity mediated the relationship between hand squeezing and motor performance (distance from the target). ConclusionThe EEG results suggest that pre-performance unilateral hand contractions influence the extent of verbal-analytical engagement during motor planning, which in turn influences motor performance. However, the hand contractions did not influence cardiac activity, muscle activity or kinematics.