a deep breath and using controlled exhalations to blow through the flute, helping with exercising the lungs. Ergonomics Contemporary Native American flutes can take ergonomic considerations into account, even to the point of custom flute designs for individual flute players. However, the ergonomic issues related to these instruments are not well-studied and ergonomic designs are not widespread; one study reported that 47–64% of players reported physical discomfort at least some of the time, while over 10% of players reported moderate discomfort on an average basis. Sound and tuning The predominant scale for Native American flutes crafted since the mid-1980s (often called "contemporary Native American flutes") is the pentatonic minor scale. The notes of the primary scale comprise the root, minor third, perfect fourth, perfect fifth, minor seventh, and the octave. Recently some flute makers have begun experimenting with different scales, giving players new melodic options. The pitch standard used by many Native American flutes before the mid-1980s was arbitrary. However, contemporary Native American flutes are often tuned to a concert pitch standard so that they can be easily played with other instruments. The root keys of contemporary Native American flutes span a range of about three and a half octaves, from C2 to A5. Early recordings of Native American flutes are available from several sources. Fingering Native American flutes typically have either five or six finger holes, but any particular instrument may have from zero to seven finger holes. The instrument may include a finger hole covered by the thumb. The fingerings for various pitches are not standardized across all Native American flutes. However, many contemporary Native American flutes will play the primary scale using the fingering shown in the adjacent diagram. While the pentatonic minor scale is the primary scale on most contemporary Native American flutes, many flutes can play notes of the chromatic scale using cross-fingerings. Tuning Native American flutes are available in a wide variety of keys and musical temperaments—far more than typically available for other woodwind instruments. Instruments tuned to equal temperament are typically available in all keys within the range of the instrument. Instruments are also crafted in other musical temperaments, such as just intonation, and pitch standards, such as A4=432 Hz. Warble A distinctive sound of some Native American flutes, particularly traditional flutes, is called a warble (or warbling). It sounds as if the flute is vacillating back and forth between distinct pitches. However,