Consistency of performance-related emotions in elite athletes: Generalizability theory applied to the IZOF
Performance affect in soccer players: An application of the IZOF
Although the purpose of this study was not to test the theoretical foundations of the IZOF
model, results nevertheless seem to provide one possible explanation as to why individuals differ in their zones of optimal functioning.
2008) Functional impact of emotions on athletic performance: Comparing the IZOF
model and the directional perception approach.
In its earlier version, the IZOF model was proposed by Hanin (1980, 1986) to account for the wide variability in state anxiety scores often found in field studies across contestants of different sports.
The IZOF model has been more recently extended beyond anxiety to include a wide range of idiosyncratic positive (pleasant) and negative (unpleasant) affect facilitating or inhibiting performance (Hanin, 1993, 1997, 2000b, 2000c).
Most research so far conducted within the IZOF framework employed idiosyncratic scales of emotion adjectives, but disregarded physiological descriptors or states associated with emotions.
Simply stated, the IZOF notion holds that each individual has an optimal range of state anxiety where he or she performs best.
The IZOF model has been recently extended to comprise positive and negative emotions other than anxiety.
Investigations designed to test the expanded IZOF model comprising emotions other than anxiety are to date quite scarce, and measures used were emotions and performance (Robazza, Bortoli, & Nougier, 1999; Robazza, Bortoli, Zadro, & Nougier, 1998; Syrja, Hanin, & Pesonen, 1995; Syrja, Hanin, & Tarvonen, 1995; for discussion, see Gould & Tuffey, 1996; Hanin, 1997).
Original IZOF work (Hanin, 1980, 1986) focused on pre-competitive state anxiety framework using Spielberger's (1983) State Trait Anxiety Inventory (STAI).
However, Jokela and Hanin (1997) indicated that IZOF data was heterogeneous and 88% of the variance from retrospective recall was left unexplained.