Here is the design of a clinical trial:

Official Title: Effets de la tDCS Sur la Performance Sportive de 2 Profils d'athlètes : Explosifs (Sauteurs de Haut Niveau et Amateur) et Endurants (Cyclistes de Haut Niveau et Amateur)

Included conditions:
- Healthy Volunteers
- High-level Sportsman

Study Armgroups:
- {'label': 'Group S1', 'type': 'EXPERIMENTAL', 'description': 'High level jump practice : more 4000 hours of practice during the last five years', 'interventionNames': ['Device: Active tDCS', 'Device: Sham tDCS']}
- {'label': 'Group S2', 'type': 'EXPERIMENTAL', 'description': 'Amateur jump practice : less 4000 hours of practice during the last five years', 'interventionNames': ['Device: Active tDCS', 'Device: Sham tDCS']}
- {'label': 'Group C1', 'type': 'EXPERIMENTAL', 'description': 'High level cycling practice: more 4000 hours of practice during the last five years', 'interventionNames': ['Device: Active tDCS', 'Device: Sham tDCS']}
- {'label': 'Group C2', 'type': 'EXPERIMENTAL', 'description': 'Amateur cycling practice: less 4000 hours of practice during the last five years', 'interventionNames': ['Device: Active tDCS', 'Device: Sham tDCS']}
- {'label': 'Group T', 'type': 'EXPERIMENTAL', 'description': 'Sedentary : less two hours of recreationally practice of sport by week', 'interventionNames': ['Device: Active tDCS', 'Device: Sham tDCS']}

Interventions:
- {'type': 'DEVICE', 'name': 'Active tDCS', 'description': '2 active tDCS sessions (20 min each, 2 mA) applied to the dlPFC and right motor cortex', 'armGroupLabels': ['Group S1', 'Group S2'], 'otherNames': ['Starstim® (Neuroelectrics, Spain)']}
- {'type': 'DEVICE', 'name': 'Sham tDCS', 'description': '1 sham tDCS session (20 min, 0 mA) applied to the dlPFC', 'armGroupLabels': ['Group S1', 'Group S2'], 'otherNames': ['Starstim® (Neuroelectrics, Spain)']}
- {'type': 'DEVICE', 'name': 'Active tDCS', 'description': '10 tDCS sessions (2 sessions/day for 5 days, 20 mA, 20 min each) applied to the dlPFC', 'armGroupLabels': ['Group C1', 'Group C2', 'Group T'], 'otherNames': ['Starstim® (Neuroelectrics, Spain)']}
- {'type': 'DEVICE', 'name': 'Sham tDCS', 'description': '10 tDCS sessions (2 sessions/day for 5 days, 0 mA, 20 min each) applied to the dlPFC', 'armGroupLabels': ['Group C1', 'Group C2', 'Group T'], 'otherNames': ['Starstim® (Neuroelectrics, Spain)']}

Primary Outcomes:
- {'measure': 'Performance (in meters) measured during jumps', 'description': 'Performance measurement (in meters) during the three types of jumps (long jump, squat jump and countermovement jump) before and after tDCS session', 'timeFrame': 'Day 5'}

Please estimate the sample size based on the assumption: 
Considering a significance level of 5%, a power of 90%, and a standard deviation for paired differences of 6.5.
Sample size
        Our sample size calculation is based on the primary efficacy outcome that relates to changes in motor performance before and after a tDCS session during an explosive task (jumps). In a previous study, Lattari et al. [22] showed an 11.2% improvement in the height of the CMJ following a tDCS session, corresponding to a difference of 3.9âcm (Table 1 of Lattariâs et al.). We expect a 15% improvement in our study corresponding to a difference of 5.1âcm. No difference is expected in the sham tDCS group. Considering a significance level of 5%, a power of 90%, and a standard deviation for paired differences of 6.5 (calculated from standard deviations, page 21, Table 1 with an hypothesis of a covariance of measures of 50%), 20 jumpers are included to meet the objectives of the study. Sample size calculation was performed on PASS 13 Power Analysis and Sample Size Software (2014) [39, 40] .