Excessive physical activity:IPAQ quantifying the activity physical according vigorous intensity activities at least 3 days per week adding a minimum total physical activity of at least 1500MET-minutes / week or 7 or more days any combination of walking, moderate intensity or vigorous intensity activities a total minimum of physical activity of at least 3,000 MET-minutes / week

Ideal Physical activity: IPAQ quantifying the activity physical according 3 days or more of vigorous intensity physical activity at least 20 minutes per day or 5 or more days of moderate intensity and / or walk at least 30 minutes per day or 5 or more days of any combination of walking, moderate-intensity activity and activity vigorous intensity for a total minimum of physical activity of at least 600 MET-minutes / week.

IPAQ quantifying the activity physical according Insufficient physical activity: Individuals who can not put on the criteria of the above categories.

all candidates for sperm donors clinic IVI IVI Bilbao and Valencia were will provide the international physical activity questionnaire (IPAQ) attached to analyze the total physical activity. This will be self-completed questionnaire beforeSperm donation. (Appendix 1) Age, snuff, weight, BMI, alcohol, drug use and the type of sport that practices will be analyzed: Additionally a tab for each donor collecting the existence of associated factors be drawn. (Appendix 2)

Semen parameters will be evaluated according to WHO criteria blinded on clinical and data analyst.

International Physical Activity Questionnaire (IPAQ) offers before sperm donation quantifying the activity "walk", "activities of moderate intensity" and "vigorous intensity activities" assigned to each activity about energy requirements defined in METs, being multiples of the rate of metabolic rate equivalent to kilocalories for a 60 kg.

The median and interquartile range (between Q1 and Q3) is calculated for walking (W), activities of moderate intensity (M), activities of vigorous intensity (V) and a combined result of total physical activity. All results must be expressed as continuous METminutos / week.

The existence of confounding factors such as age, tobacco, weight, BMI, alcohol, drugs, type of sport will be cleaned and blood parameters associated with physical activity will be defined.

A data tab/sheet for each donor was made . The existence of related factors such as age, tobacco, weight, BMI, alcohol, drug and the type of sport exercised were been analysed.

It categorizes the population into quartiles depending on their activity and determine which is which is associated with a better seminal quality the same debugging is made confounding previously mentioned.

multivariate analysis to determine the correlation between physical activity and sperm parameters