Training Methodology
Triphasic Training
Triphasic training is a periodization model developed by Cal Dietz that structures training around the three phases of muscular contraction: eccentric, isometric, and concentric. Rather than treating these phases as incidental aspects of every lift, triphasic training isolates and emphasizes each phase in a dedicated training block, using specific tempo prescriptions to build maximal force production in each contraction type before integrating them into full-speed explosive movement.
The three phases
The eccentric phase is the loading or lowering portion of a movement, where the muscle produces force while lengthening. Triphasic training targets this with slow, controlled lowering phases (typically three to six seconds) at high loads. The isometric phase occurs at the transition between eccentric and concentric movement, where the body must absorb and redirect stored elastic energy. Triphasic training trains this with paused reps held for two to three seconds at the bottom of the movement. The concentric phase is the lifting or explosive portion. After developing force production in the eccentric and isometric phases, concentric-dominant and ballistic work builds the ability to express that force at high velocity.
Why it has been widely adopted at the collegiate level
Dietz developed the model at the University of Minnesota and its adoption spread largely through the strength coaching community at the college level. The model addresses a gap that many coaches recognized: athletes often improve their 1RM without corresponding improvements in reactive and elastic performance. By deliberately training each phase of the contraction, triphasic training builds both maximal strength and the force absorption and redirection qualities that transfer most directly to sport performance. The tempo prescriptions also make loading intent explicit, which improves coaching consistency across large groups of athletes.
Related terms
Eccentric Training · Isometric Training · Tempo Notation · Block Periodization · RFD (Rate of Force Development)