I think one of the most valuable lessons I've learned as a coach is how to connect with my athletes/clients on a daily basis. So often we see coaches or trainers draw up a program or practice plan and become so in love with the plan that they do whatever they have to do to fit the player/athlete to the plan, when in reality it needs to be vice versa.
I've talked before about the value of foam rolling, not only in improving tissue quality and overall muscle function of the users, but also in giving myself time to walk around and get an idea for how each person is feeling prior to a workout. If people are feeling crappy, were up all night doing school work, skipped the last meal, etc., then there isn't a lot to be gained from a super intense workout. With the "old-school" mentality this might be considered soft. And to be honest sometimes it is. But, as a coach, it's important to learn your athletes. Not all answers are created equal when asking these questions. For example, if you know a kid comes in complaining about something every day (we've all had them), and you ask him how he feels and he says "eh, so-so," you better believe he's getting pushed.
Now, if your team leader, who never says "boo" even when in severe pain, comes to you with that same "so-so" sentiment, what would you do? Would you make him push through a rigorous strength workout? Or would you back off, maybe do some mobility/recovery work and possibly even teach some new skills at a lower intensity? Which do you think would be more productive in the long run?
The problem with this type of training has been the complete subjectivity involved in the programming. You absolutely need a long-term plan in order to do this; having goals makes it easier to deviate from the plan when necessary, only to find your way back to it as soon as possible. However, it's hard to find solid research to back up this type of approach because of the lack of objectivity no matter how much sense it makes in practice.
I did stumble across a recent article that gave a fancy name to this style of coach called "Flexible Non-Linear Periodization". While I didn't totally agree with some of their testing methods for strength, the improvements in long-term (16 weeks) strength were significantly higher in athletes who were allowed to adjust their workouts based on how they felt that day. The overall volume and total repetitions were controlled for between groups, but the FNLP group sustained much greater gains over time.
This is a strategy that allows coaches to make for highly individualized programming within small groups, maximizing efficiency and use of time without sacrificing the individual attention that most want. The tactic has served me well working with young athletes ranging from age 10 all the way through adults and weekend-warriors. If you're not taking into account the activities your clients are doing outside of your watch, I believe you are doing them a huge disservice.
If you're interested in the study here is the citation:
McNamara, JM and Stearne, DJ. Flexible nonlinear periodization in a beginner college weight training class. Journal of Strength and Conditioning Research 24(1): 17-22, 2010.