Marshall et al. (2011) recently published the results of a comprehensive strength training study investigating the effect of the number of sets used in each training session on muscle function, hypertrophy and activation [assessed by electromyography (EMG)] in men with previous weight training experience [mean squat lift load = 159.9 kg (1.9 9 body mass)]. Squat lift training was performed at 80% of 1 RM to exhaustion twice weekly for 6 weeks, then a combination of heavier (4–12 RM) and lighter, explosive (e.g. jump squat) exercises were performed for 4 weeks. The results were very interesting, revealing that the performance of eight sets of exercises was superior to one and four sets for muscle strength improvement in their cohort. One intriguing result was that the rate of force development (RFD), measured during an isometric knee extension test, did not improve with training despite there being a small increase in the rate of muscle activation (measured as the rate of integrated EMG increase) in addition to the substantial (11.7–22.8%) increase in strength. On their own, each of these adaptations could have been expected to result in an increase in RFD (Aagaard et al. 2002). From this, it could be concluded that the preponderance of slowspeed dynamic exercises was not appropriate to improve RFD, or that the use of an isometric test was inappropriate. These opinions make sense given our understanding of the specificity of adaptations to strength training. However, the question should be asked: does the published research support these assertions? Numerous studies have reported significant enhancements in RFD measured in the isometric knee extension test after traditional, explosive or isometric strength training of the lower extremity (e.g. Aagaard et al. 2002; Blazevich et al. 2009; Blazevich et al. 2008; Del Balso and Cafarelli 2007; Hakkinen et al. 2003; Hakkinen et al. 2001a, b; Narici et al. 1996; Reeves et al. 2003; Suetta et al. 2004; Vila-Cha et al. 2010). In each of these studies, some portion of test-specific training was performed as part of the program. That is, the knee extension training was performed in training, so there was at least some similarity (specificity) between the testing and training tasks with respect to body position. The same result is seen when training is done in other muscle groups, including the trapezius (Andersen et al. 2009), elbow flexors (Barry et al. 2005; Gabriel et al. 2001), plantarflexors (Holtermann et al. 2007) and dorsiflexors (Geertsen et al. 2008), or when a multi-joint isometric leg press test is used to assess RFD after a period of dynamic leg press training (Hoff et al. 2007; Husby et al. 2009; Mosti et al. 2011; Wang et al. 2010). Of the studies cited here, the mean improvement in absolute RFD was 42.6% (mean of all published results), which, when the results are expressed as the sample size-weighted mean, equates to a 4.4% increase per week. Interestingly, there appears to be no clear evidence that there is a requirement for fast force production during the training, with increases of only 8.0% at 0.4% per week when some form of explosive training was performed compared to 31.3% at 1.3% per week when slower strength training was performed. In fact, the evidence more clearly supports the reverse hypothesis, and it is rarely seen that strength training is not associated with an increase in RFD measured isometrically (Hakkinen et al. 1998; Sleivert et al. 1995). Thus, the overwhelming Communicated by Susan A. Ward.