# Evidence-based vs. social media based high-intensity interval training protocols: Physiological and perceptual responses PMID: 34587217 Journal: PloS one Published: 2021-09-29 Authors: Hesketh KL, Church H, Kinnafick F, Shepherd SO, Wagenmakers AJM, Cocks M, Strauss JA ## Question Do HIIT protocols promoted on social media produce similar acute physiological, perceptual, and motivational responses to evidence-based laboratory and bodyweight HIIT protocols? ## Summary This randomized counterbalanced crossover study compared acute heart-rate, lactate, affect, enjoyment, and perceived competence responses to four single-session HIIT protocols in young recreationally active adults: two evidence-based protocols and two social-media video protocols. Bodyweight 60:60 HIIT produced physiological responses similar to laboratory cycling 60:60 HIIT and was more enjoyable than cycling and one social-media protocol. The 20:10 social-media protocol generated less time above 80% HRmax and lower lactate than the established protocols, showing that short, popular HIIT videos may not all produce equivalent high-intensity stimuli. ## Population - Young recreationally active adults completing more than 1 but fewer than 4 structured exercise sessions per week. - Sample size: 27 - Age: 22 +/- 3 years - Sex: 13 male, 14 female - Fitness level: Recreationally active; VO2peak 42.2 +/- 7.2 ml/min/kg. - Health status: Apparently healthy; excluded cardiovascular or metabolic disease, pregnancy/breastfeeding, and current injury. ## Methodology - Randomized, counterbalanced crossover acute exercise study with four HIIT protocol visits after an initial maximal exercise test. - Single acute exposure to each of four protocols; visits separated by at least 48 hours. - Laboratory at Liverpool John Moores University; all protocol visits between 11am and 3pm. - Randomized and controlled study design. ## Protocol - Four acute HIIT protocols: Ergo-60:60, BW-60:60, SM-20:10, SM-40:20. - Modality: Cycling and bodyweight exercise circuits. - Work intervals: 60 seconds, 20 seconds, or 40 seconds depending on protocol. - Recovery: 60 seconds, 10 seconds plus inter-set rest, or 20 seconds depending on protocol. - Sets or repetitions: 10 intervals for Ergo-60:60 and BW-60:60; 20 intervals across 5 sets for SM-20:10; 15 intervals for SM-40:20. - Intensity: 100% Wmax for cycling; as many repetitions as possible or video-guided self-paced bodyweight exercise; HR target assessed as >=80% HRmax. - Session duration: 11.5 to 20 minutes excluding 2-minute warmup. - Frequency: One exposure per protocol in crossover design. - Program length: Acute single-session protocol comparison. - Progression: None. ## Outcomes ### Time above HR >=80% HRmax Status: mixed SM-20:10 produced significantly less time above the high-intensity HR criterion than all other protocols, while Ergo-60:60, BW-60:60, and SM-40:20 were not different from each other. Ergo-60:60 13.9 +/- 4.9 min, BW-60:60 13.5 +/- 3.5 min, SM-40:20 12.1 +/- 2.4 min, SM-20:10 7.7 +/- 3.1 min; P<0.001. ### Proportion of intervals meeting HR >=80% HRmax Status: mixed BW-60:60 had a higher proportion of intervals meeting the HR criterion than SM-20:10. BW-60:60 93 +/- 10%, SM-20:10 74 +/- 20%, P=0.039; overall P=0.005. ### Blood lactate Status: mixed SM-20:10 produced a smaller lactate increase than Ergo-60:60 and BW-60:60. SM-20:10 +5.5 +/- 2.6 mmol/L vs Ergo-60:60 +7.4 +/- 2.6 mmol/L, P=0.002, and BW-60:60 +7.7 +/- 3.7 mmol/L, P<0.001. ### Enjoyment Status: mixed BW-60:60 was more enjoyable than cycling Ergo-60:60 and social-media SM-40:20. Interest/enjoyment subscale: BW-60:60 5.0 +/- 1.2 vs Ergo-60:60 4.4 +/- 1.2, P=0.020, and SM-40:20 4.3 +/- 1.2, P=0.008. ## Practical Insights - A bodyweight 10 x 60-second protocol with 60-second recovery may be a strong app candidate because it matched cycling physiological stimulus and had higher enjoyment. - Popular social-media HIIT formats should not be assumed to create equivalent physiological stimulus; short 20:10 circuits may underdose time above target HR. - Perceived competence and exercise selection should be treated as programming variables, not cosmetic details. ## Limitations - Acute study only; no long-term training adaptations or adherence outcomes. - Small young recreationally active sample. - Lab setting may not reflect home, gym, or outdoor HIIT experience. - Protocols differed in duration, work-rest ratio, exercise mode, and imposed versus self-selected intensity, limiting isolation of causal protocol components. - Findings cannot be generalized to all HIIT protocols or all social-media videos. ## Safety And Adherence - One participant could not finish the Ergo-60:60 cycling protocol due to fatigue. - Researchers provided technique correction to minimize injury risk during bodyweight protocols. - No adverse events were reported in the extracted full text. ## Original Sources - [PubMed](https://pubmed.ncbi.nlm.nih.gov/34587217/) (pubmed) - [DOI](https://doi.org/10.1371/journal.pone.0257685) (doi) - [PMC full text](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8480907/) (full text) ## Agent Guidance Preserve the paper-level scope of this note. Do not generalize beyond the population, protocol, measured outcomes, and limitations above.