The frequency of anterior cruciate ligament injuries (ACL) by non-contact aetiologies (Rees, 1994) and the potentially severe consequences for the team games player (Kujala et al., 1995) has underscored the need for understanding of the importance of neuromuscular mechanisms in the effective maintenance of knee joint integrity (Gleeson et al., 1998a). In particular, the knee flexor muscle group offers greatest dynamic protection against injuries to this ligament (Johansson, 1991). Traditional (volitional) methods of assessment of neuromuscular performance can be confounded by inhibitory mechanisms (Gleeson, 200 1). Accordingly, the painless technique of magnetic stimulation of peripheral nerves has received increased attention for the assessment of aspects of 'true' neuromuscular capacity (King and Chippa, 1989). There is accumulating evidence that implies a linkage between fatigue and injury (Gleeson et al., 1998b; Hawkins et al., 2001). However, further investigation is required to explore how such exercise may affect 'true' performance capacity and the possible implications for knee joint stability. Estimates of indices of neuromuscular performance, such as electromechanical delay, rate of force development and time to half peak force, may offer important information concerning the temporal capabilities of the active joint stabilisers, to initiate and muster meaningful levels of muscle force. These estimates may also provide an insight into the likely knee injury avoidance capabilities (Gleeson et al., 1998b; Mercer et al., 1998). However, only limited information is available in the contemporary scientific literature regarding the reproducibility and reliability characteristics of these indices of performance for the knee flexors, particularly subsequent to magnetic stimulation.