Here is the design of a clinical trial:

Official Title: Prevention of Leg Cramps Using Compression Stockings or Magnesium Supplements in the Age Group of 50 to 84: a Study Protocol for a Randomised Controlled Trial

Included conditions:
- Muscle Cramp
- Stockings, Compression
- Magnesium

Study Armgroups:
- {'label': 'Compression stocking', 'type': 'EXPERIMENTAL', 'description': "Compression stockings are mainly used for the prevention and reduction of lower limb oedema or venous thrombosis. There are three compression classes used in health care. The compression stocking group of the study will receive CE-marked stockings within the compression class of 1 (25-40 mmHg compression). The correct size for the compression stockings will be defined by the reported circumference of the participant's ankle and calf. The participants will be given instructions to put the stockings on immediately after getting out of bed in the morning and to take them off before going to bed in the evening for the last four weeks of the study. Stockings within the mild compression class have no harmful effects on individuals when the exclusion criteria are considered. The participants will be instructed to communicate with a dedicated research assistant via e-mail or phone in case of any problems or questions.", 'interventionNames': ['Other: Compression stocking']}
- {'label': 'Magnesium', 'type': 'ACTIVE_COMPARATOR', 'description': 'Magnesium is a mineral substance which regulates many biochemical reactions in the body, for example protein synthesis and the function of the muscles and nerves. It has a significant role in controlling blood sugar, blood pressure, energy generation and the formation of the bones. The recommended dietary allowance for magnesium is 420 mg for males and 320 mg for females over 50 years old. Dark green vegetables, leguminous plants, nuts, seeds and wholegrains are good sources of magnesium (11,12).\n\nIn the average Finnish diet, the recommendation is usually exceeded, and excessive amounts of magnesium in the body are extremely rare. The magnesium arm of the study will take oral tablets containing 620 mg of magnesium hydrochloride daily for the last four weeks of the study, which is equivalent to 250 mg of pure magnesium per day. The magnesium tablets for this study were manufactured and analysed by the Pharmia pharmaceutical company in Finland.', 'interventionNames': ['Dietary Supplement: Magnesium tablet']}
- {'label': 'Placebo', 'type': 'PLACEBO_COMPARATOR', 'description': 'The placebo tablets will consist of microcrystalline cellulose, magnesium stearate (anti-caking agent) and silicon dioxide. The placebo tablets were manufactured and analysed by the Pharmia pharmaceutical company in Finland. The placebo arm will receive placebo tablets to be taken daily for the last four weeks of the study. The participants will not know whether they are randomised into the magnesium arm or the placebo arm. The packaging and the appearance of the placebo and magnesium tablets are identical.', 'interventionNames': ['Other: Placebo tablet']}

Interventions:
- {'type': 'OTHER', 'name': 'Compression stocking', 'description': 'Please see the description of the intervention in another section', 'armGroupLabels': ['Compression stocking']}
- {'type': 'DIETARY_SUPPLEMENT', 'name': 'Magnesium tablet', 'description': 'Please see the description of the intervention in another section', 'armGroupLabels': ['Magnesium']}
- {'type': 'OTHER', 'name': 'Placebo tablet', 'description': 'Please see the description of the intervention in another section', 'armGroupLabels': ['Placebo']}

Primary Outcomes:
- {'measure': 'The change in quantity of leg cramps', 'description': "The change in quantity of leg cramps from the four-week follow-up period (prior to the intervention) to the four-week intervention period will be assessed on the basis of the participants' responses to the survey. The number of cramps will be recoded on a weekly online survey during four weeks before intervention and during the four-week intervention period. The change in the number of cramps from the four-week period prior the intervention to the intervention period will be calculated. The difference between groups will be analyzed by one-way analysis of variance of repeated measurements.", 'timeFrame': '8 weeks'}

Please estimate the sample size based on the assumption: 
Power of 80%, significance level of 0.05, and a drop-out rate of 30%
Sample size {14}
        The projected number of participants is based on sample size calculations, in which a power of 80% and significance level of 0.05 will show a difference between the intervention groups in the reduction of the quantity of leg cramps when variance analysis is used in statistical testing. The calculations for the minimum sample size are based on three of Cohenâs (1988) suggested effect sizes for f variance analysis. When the effect size of 0.25 and a drop-out rate of 30% are used, the number of applicable participants should be a minimum of 225 persons.