Effects of Afternoon Napping, Caffeine, and a Standardised Active Recovery Protocol on Evening Athletic Performance According to Sex and Chronotype: A Randomised Crossover Trial
试验速览
- 阶段
- 不适用
- 状态
- 已完成
- 发起方
- 入组人数
- 60
- 试验地点
- 1
- 主要终点
- Repeated Modified Agility Test (RMAT) Total Time
研究概览
简要总结
This study evaluated whether afternoon napping, caffeine ingestion, and a standardised active recovery and nutritional protocol could influence evening physical and cognitive performance in healthy university athletes.
Participants completed five experimental conditions in a randomised crossover design: placebo without napping, napping with placebo, caffeine without napping, napping combined with caffeine, and napping combined with caffeine plus a standardised active recovery and nutritional protocol. The nap opportunity lasted 90 minutes and caffeine was administered at 5 mg/kg body mass.
The main outcome was repeated agility performance. Additional outcomes included sprint performance, jumping performance, reaction time, subjective sleepiness, sleep characteristics during the nap opportunity, and selected physiological measures. The study also explored whether responses differed according to sex and chronotype.
详细描述
This randomised, placebo-controlled crossover study examined the isolated and combined effects of afternoon napping, caffeine ingestion, and a standardised active recovery and nutritional protocol on evening athletic performance.
Participants completed five experimental conditions in a counterbalanced Latin-square order, with at least 72 h between sessions:
- PLA: placebo capsule at 18:00, without a nap opportunity.
- NAP: 90-min nap opportunity from 13:00 to 14:30 plus placebo capsule at 18:00.
- CAF: caffeine ingestion at 18:00 (5 mg/kg body mass) without a nap opportunity.
- NAP+CAF: 90-min nap opportunity plus caffeine ingestion at 18:00.
- NAP+CAF+REC: 90-min nap opportunity plus caffeine ingestion at 18:00 and a standardised active recovery and nutritional protocol from 18:45 to 19:00.
The active recovery and nutritional protocol included a standardised lower-limb dynamic stretching routine followed by a carbohydrate-protein snack containing 20 g maltodextrin and 10 g whey isolate. The protocol was identical for all participants allocated to this condition.
Participants were stratified by sex and chronotype before condition allocation. Capsule allocation was double-blinded: participants, outcome assessors, and the testing team were unaware of whether caffeine or placebo had been administered. Blinding of nap and active recovery components was not possible because of the nature of these interventions.
研究设计
- 研究类型
- Interventional
- 分配方式
- Randomized
- 干预模型
- Crossover
- 主要目的
- Other
- 盲法
- Triple (Participant, Investigator, Outcomes Assessor)
盲法说明
Double-blind, placebo-controlled design. Participants and investigators conducting the testing battery are blinded to condition assignment. The researcher preparing the capsules and the statistician are separate from the testing team. Blinding is maintained until final data analysis.
入排标准
- 年龄范围
- 18 Years 至 25 Years（Adult）
- 性别
- All
- 接受健康志愿者
- 是
入选标准
- •Healthy university athletes aged 18-25 years.
- •Regular engagement in structured training, defined as at least 10 training sessions per week of approximately 2 h each, across team sports, judo, athletics, tennis, or swimming.
- •Non-habitual napping, defined as fewer than one nap per week.
- •Low habitual caffeine intake, defined as <80 mg/day, assessed using a 7-day dietary recall.
- •Non-smoker and free from regular medication or recreational drug use.
- •No musculoskeletal injury during the preceding month.
- •Good self-reported sleep quality, defined as a Pittsburgh Sleep Quality Index score <
- •Definite morning chronotype (MEQ score 59-86) or definite evening chronotype (MEQ score 16-41).
- •For female participants: self-reported regular menstrual cycles (26-32 days), no hormonal contraceptive use, and no self-reported history of menstrual disorders.
排除标准
- •Intermediate chronotype (MEQ score 42-58).
- •Habitual napping (≥1 nap per week).
- •Habitual caffeine intake ≥80 mg/day.
- •Smoking, regular medication use, or recreational drug use.
- •Musculoskeletal injury during the preceding month.
- •Pittsburgh Sleep Quality Index score ≥
- •Self-reported irregular menstrual cycles, hormonal contraceptive use, or history of menstrual disorders in female participants.
- •Self-reported sleep disorder.
- •Inability or unwillingness to complete all five experimental conditions.
研究组 & 干预措施
PLA
Placebo capsule (microcrystalline cellulose) at 18:00, no nap opportunity
干预措施: Placebo (Other)
NAP+CAF+REC
90-minute afternoon nap opportunity (13:00-14:30) with EEG recording, caffeine ingestion (5 mg/kg) at 18:00, plus 15-minute personalised active recovery protocol (18:45-19:00) consisting of dynamic stretching and a carbohydrate-protein snack (20g maltodextrin + 10g whey isolate).
干预措施: Caffeine (Dietary Supplement)
NAP+CAF
90-minute afternoon nap opportunity (13:00-14:30) with EEG recording, followed by caffeine ingestion (5 mg/kg) at 18:00.
干预措施: Caffeine (Dietary Supplement)
CAF
Caffeine ingestion (5 mg/kg body mass of anhydrous caffeine) at 18:00, no nap opportunity. Participants remained in a quiet, dimly lit room during the 13:00-14:30 period.
干预措施: Caffeine (Dietary Supplement)
NAP
90-minute afternoon nap opportunity (13:00-14:30) with objective sleep architecture recording via portable EEG headband (Dreem 3), followed by placebo capsule (microcrystalline cellulose) at 18:00. Participants remained in a quiet, dimly lit room during the nap opportunity.
干预措施: Afternoon Nap (Behavioral)
NAP
90-minute afternoon nap opportunity (13:00-14:30) with objective sleep architecture recording via portable EEG headband (Dreem 3), followed by placebo capsule (microcrystalline cellulose) at 18:00. Participants remained in a quiet, dimly lit room during the nap opportunity.
干预措施: Placebo (Other)
NAP+CAF
90-minute afternoon nap opportunity (13:00-14:30) with EEG recording, followed by caffeine ingestion (5 mg/kg) at 18:00.
干预措施: Afternoon Nap (Behavioral)
NAP+CAF+REC
90-min afternoon nap opportunity (13:00-14:30) with portable EEG monitoring, caffeine ingestion (5 mg/kg body mass) at 18:00, and a 15-min standardised active recovery and nutritional protocol from 18:45 to 19:00. The protocol included lower-limb dynamic stretching followed by a carbohydrate-protein snack containing 20 g maltodextrin and 10 g whey isolate.
干预措施: Afternoon Nap (Behavioral)
结局指标
主要结局
Repeated Modified Agility Test (RMAT) Total Time
时间窗: At approximately 19:35 on each of the five experimental days
Total time (seconds) to complete 10 maximal 20-m sprints with four changes of direction (forward sprint, left shuffle, right shuffle, backward sprint). The test was conducted on an indoor hardwood court using dual-beam photocells (Brower Timing Systems, Salt Lake City, UT, USA) placed at the start/finish line. Participants started from a standing position 0.5 m behind the first photocell. Lower values indicate better repeated agility performance. This was the primary outcome measure used for sample size calculation.
次要结局
- Countermovement Jump (CMJ) Height(At approximately 19:20 on each of the five experimental days.)
- Squat Jump (SJ) Height(At approximately 19:25 on each of the five experimental days.)
- 20-m Sprint Time(At approximately 19:45 on each of the five experimental days.)
- Simple Reaction Time (SRT)(At approximately 19:15 on each of the five experimental days.)
- Choice Reaction Time (CRT)(At approximately 19:20 on each of the five experimental days.)
- Heart Rate Variability (RMSSD and HF Power)(At 12:00, 18:00, and approximately 19:45 on each of the five experimental days.)
- Salivary Cortisol Concentration(At 12:00, 18:00, approximately 19:45, and 30 minutes after exercise on each of the five experimental days.)
- Plasma Brain-Derived Neurotrophic Factor (BDNF)(Measured at baseline and after completion of the evening testing battery on each experimental day.)
- Blood Lactate Concentration(At 18:55, 3 minutes after the Repeated Modified Agility Test, and 3 minutes after the 20-m sprint on each of the five experimental days.)
- Nap Architecture (EEG)(During the 90-minute nap opportunity from 13:00 to 14:30 on NAP, NAP+CAF, and NAP+CAF+REC condition days only.)
研究者
Kais Elabed
Principal Investigator
The Higher Institute of Sport and Physical Education of Sfax