Push-ups are an ubiquitous resistance training exercise. While exhibiting a relatively similar upper body motion to the bench press, there are substantial differences in repetitions when employing similar relative loads. The objective was to examine sex-related differences in repetitions and muscle activation associated with push-ups and bench press exercises. Twenty resistance-trained participants (10 men [22 ± 6.1 years] and 10 [24 ± 5.7 years] women) performed maximum push-up and bench press repetitions with loads relative to the body mass during a push-up. Electromyographic (EMG) electrodes were positioned on the middle and anterior deltoids, triceps and biceps brachii, and pectoralis major muscles and their relative (normalized to a maximum voluntary contraction) activity was compared between the two exercises performed to task failure. Both females (3.5 ± 3.9 vs.15.5 ± 8.0 repetitions; p = 0.0008) and males (12.0 ± 6.3 vs. 25.6 ± 5.2 repetitions; p < 0.0001) performed 77.4% and 53.1% less bench press than push-up repetitions respectively. Males significantly exceeded females with both push-ups (p = 0.01) and bench press (p = 0.004) repetitions. Significant linear regression equations were found for females (r² = 0.55; p = 0.03), and males (r² = 0.66; p < 0.0001) indicating that bench press repetitions increased 0.36 and 0.97 for each push-up repetition for females and males respectively. Triceps (p = 0.002) and biceps brachii (p = 0.03) EMG mean amplitude was significantly lower during the push-up concentric phase, while the anterior deltoid (p = 0.03) exhibited less activity during the bench press eccentric phase. The sex disparity in repetitions during these exercises indicates that a push-up provides a greater challenge for women than men and regression equations may be helpful for both sexes when formulating training programs.