Weight training question

Variety keeps the muscles 'guessing' and that sparks change and gowth.

I'd recommend block periodisation to any athlete. Strength and conditioning research on block (linear) periodisation has also shown positive effects on increases in strength, speed, and power. Kraemer (Kraemer, 1997) demonstrated the superiority of periodisation vs. non-periodisation when training football players.

Undulating periodisation involves the acute variation of volume and intensity on a weekly (microcycle) or daily basis. According Poliquin, this type of scheduling allows for minimal risk of overtraining and plateau like adaptation, while allowing for maximal training effect. This, in contrast to linear block training models, which “lose their efficacy after only two weeks” (Wilson and Wilson, 2005, Poluquin et al, 1985).  In his investigation, Poliquin concluded, “that if the stimulus is provided in the exact same way, results would diminish over time (Wilson and Wilson, 2005,Poluquin, 1988 ).” This theory holds true to Seyle’s general adaptation theory, in that there needs to be exposure to stimulus or stress for adaptation to occur (Siff, 2003). Utilizing the undulating periodisation model with what he refers to as an “Accumulation Phase” where the main stressor is volume and an “Intensification Phase” where intensity is the main stressor. The aforementioned Dr. Bondarchuk stated the importance of “block” periodization, but included in each block must be an undulation of load and intensity. He states “we are convinced that loads of different intensities should be used in the workouts of highly qualified athletes in each session during the preparatory and competitive periods. Skilful alternation of these loads will help the athlete to learn and improve technique, develop the needed speed-strength, and obtain the best post workout restoration (Bondarchuk, 1994).

Granted there will be weeks during your macro-cycle where there will be overlaps and that it completely acceptable, Research has shown that combining strength and power training concurrently proved better in increasing vertical leap than strength or power training alone (Adams et al, 1992). In contrast though, when strength training was combined with heavy endurance training, strength (Hickson, 1980) and power (Dudley and Djamil, 1985) levels were lower than those whom did strength training alone. 

It's all about maximising your potential, whilst reducing the risks. No training program ever going to be perfect, but did it's mean that we're not going to keep trying to make them better.

Also muscle confusion is almost as bad as saying resistance training will make you a bodybuilder, muscle confusion comes from increasing overload and detraining.