def list_to_svm_line(original_list):
    """
    Concatenates list elements in consecutive element pairs.

    Parameters
    ----------
    original_list : list
        The elements to be joined

    Returns
    -------
    String
        Returns a string, resulting from concatenation of list elements in consecutive element pairs, separeted by " ".

    Example
    -------
    >>> from pymove import conversions
    >>> a = [1, 2, 3, 4, 5]
    >>> conversions.list_to_svm_line(a)
    '1 1:2 2:3 3:4 4:5'
    """
    list_size = len(original_list)
    svm_line = "%s " % original_list[0]
    for i in range(1, list_size):
        svm_line += "{}:{} ".format(i, original_list[i])
    return svm_line.rstrip()