The short version of this is that I recommend as a workout,
Three days a week
Warmup, 5-10 minutes on treadmill/bike until sweat appears
Squats, 5x 5
Overhead press, 5x 5
Rows, 5x 5
Deadlift, 5x 5
Stretches
on the lifts, it's ascending from half top weight in the first set to top weight in the last; each rep done slowly and with good form; 1-2 minutes rest between sets. Begin with just the bar for weight.
Three days a week, alternating with above
20 minutes jog, or 30 minutes brisk walk or cycle
Do whole routine for 12 weeks, then have a week off for rest and assessment of results and any new goals.
The long version is below
Sorry it's so long, but I find that if people understand the reasons for doing something one way, they're more likely to stick with it.
At what stage of training are you? Doing several exercises for the same bodypart, and doing splits, is only really indicated for intermediate or advanced trainees - more than 12 months of solid training, 12 months in which you were able to manage,
Leg strength - Squats, lifting 1.5x bodyweight for reps,
and Deadlifts, 1.75x BW
Chest/shoulder strength - Bench, 1x BW,
and Overhead press, 0.75x BW
Back strength - Bent-over barbell rows, 1x BW,
and Chin-ups, 3x 15-20
that sort of thing. The tone of your posts, it doesn't sound like you've managed that yet - sorry if I'm wrong, the rest of this assumes you're a beginner.
Until you can manage lifts like that, you're best served by a full-body workout three times a week. Not a split workout, because as a beginner you just can't work your muscles with enough intensity that they need a whole week to recover. 48 hours' recovery's enough. So work your whole body three times a week with a day off in between, like Mon/Wed/Fri.
You can do that in three exercises, one each from the pairs above. Just alternate those pairs of exercises - though if you chose just one from each pair and did just those three for three months, it would not be a bad thing.
If you have one particular area you want to focus on, then instead of three exercises do four, with the extra in that area. So in your case, you're interested in bum and legs, so you could do,
Squats
Overhead press
Rows
Deadlift
One exercise for chest/shoulders, two for back and two for legs.
Squats and deadlifts work the legs and bum.
I chose overhead press rather than bench press because if you're an office worker, probably you have slightly rounded shoulders, too. That's from all that leaning over the desk all day. Doing lots of work on a muscle tightens it - and you don't want tightened chest muscles, that'll just drag your shoulders further forwards. The overhead press works your shoulders, and your pecs only a little bit.
In truth the deadlift is a back exercise as well as a leg exercise, so two for the back. Strengthening the back is always good, but especially for an office worker, since it gets so little work during the day, and it's very common that it's sore or stiff.
As for sets and reps, as a beginner the most important thing is simply consistency. At this stage you're just learning the movements and your body is getting used to working out. The adaptations are neural more than physical.
Looking at another sport, I have got bigger muscles than Ricky Ponting, but he can throw a cricket ball faster and more accurately than me. He knows how to
apply his strength to best effect. Likewise, I can lift heavier weight than him because when it comes to barbells, I know better how to apply my strength to best effect. I've learned the movements - though still have much more to learn.
For the reasons in
this article, I recommend 5 sets of 5 reps ascending, with the first set being half the weight of the top set. For example, your squat might look like,
5x 20kg (ie just the bar), 5x 25kg, 5x 30kg, 5x 35kg, 5x 40kg
If you can make all 5 reps on all 5 sets, then in your next session add 2.5kg (1.25kg is usually the smallest plate a gym has, so 2x 1.25kg is the least you can add). And so on. If you fall short one session, can't manage all 5 reps, that's okay - try again next time.
If the
second time you can't manage it, then add another set to make up the reps. For example, if you managed,
5x 20kg, 5x 25kg, 5x 30kg, 4x 35kg, 3x 40kg
then you're 3 reps short in all, so you do 3x 40kg
If the
third workout on this weight you stall again, make the reps up as in the second workout, then in the
fourth workout
deload - take 5kg off and start the cycle again - it's like parallel parking, if you can't get in, you pull out and come in again at another angle.
Start the weight low. Start with the bar, in fact. It seems too light, that's okay - over 12 weeks you'd have 36 weights workouts, add 2.5kg each time and you go from 20 to 110kg. Probably with stalls slowing the pace of increase you'll make less on the overhead press and rows, but might make it on the squats and almost certainly on the deadlifts.
The cardio you have on other days is just enough to sustain your lifting - helps recovery between sets, and recovery between workouts.
Do the routine for 12 weeks, then have a week off with no workouts at all and reassess.
