Burke LM Practical Issues in Evidence-Based Use of Performance Supplements: Supplement Interactions, Repeated Use and Individual Responses. Sports Med. 2017 Mar;47(Suppl 1):79-100. doi: 10.1007/s40279-017-0687-1.
Chia JS, Barrett LA, Chow JY, Burns SF Effects of Caffeine Supplementation on Performance in Ball Games. Sports Med. 2017 Dec;47(12):2453-2471. doi: 10.1007/s40279-017-0763-6.
Grgic J, Trexler ET, Lazinica B, Pedisic Z Effects of caffeine intake on muscle strength and power: a systematic review and meta-analysis. J Int Soc Sports Nutr. 2018 Mar 5;15:11. doi: 10.1186/s12970-018-0216-0. eCollection 2018.
Sant'Ana J, Franchini E, da Silva V, Diefenthaeler F Effect of fatigue on reaction time, response time, performance time, and kick impact in taekwondo roundhouse kick. Sports Biomech. 2017 Jun;16(2):201-209. doi: 10.1080/14763141.2016.1217347. Epub 2016
Spriet LL Exercise and sport performance with low doses of caffeine. Sports Med. 2014 Nov;44 Suppl 2(Suppl 2):S175-84. doi: 10.1007/s40279-014-0257-8.
The Effect of Caffeine Supplementation on Blood Lactate Level, Performance and Post-Training Fatigue in Elite Basketball Players
Interventional studies are often prospective and are specifically tailored to evaluate direct impacts of treatment or preventive measures on disease.
Observational studies are often retrospective and are used to assess potential causation in exposure-outcome relationships and therefore influence preventive methods.
Expanded access is a means by which manufacturers make investigational new drugs available, under certain circumstances, to treat a patient(s) with a serious disease or condition who cannot participate in a controlled clinical trial.
Clinical trials are conducted in a series of steps, called phases - each phase is designed to answer a separate research question.
Phase 1: Researchers test a new drug or treatment in a small group of people for the first time to evaluate its safety, determine a safe dosage range, and identify side effects.
Phase 2: The drug or treatment is given to a larger group of people to see if it is effective and to further evaluate its safety.
Phase 3: The drug or treatment is given to large groups of people to confirm its effectiveness, monitor side effects, compare it to commonly used treatments, and collect information that will allow the drug or treatment to be used safely.
Phase 4: Studies are done after the drug or treatment has been marketed to gather information on the drug's effect in various populations and any side effects associated with long-term use.
