To shake up your strength workout, replace the everyone-does-'em moves (crunches, etc.) with this fresh routine created by Dixon. Do this series two to three times per week, alternating with cardio days; you'll start to see results in as little as two to three weeks. Each move hits the same major muscle groups as the old standbys, but challenges them more, giving you a stronger, sleeker body in the same amount of time. So it's efficient—in the best way possible.

Physical activity is beneficial for young people, who are naturally primed to soak up its rewards. The reality is that the majority of today’s youths, however, fall into one of two camps: Either they are athletes, engaging in one or many sports (as well as auxiliary training such as weightlifting and agility work, which can help create lifelong fitness habits) or they are sedentary.
Many of the things we do for fun (and work) count as exercise. Raking the yard counts as physical activity. So does ballroom dancing and playing with your kids or grandkids. As long as you're doing some form of aerobic exercise for at least 30 minutes a day, and you include two days of strength training a week, you can consider yourself an "active" person.

I recommend the Swanson Enhanced Pqq with Ubiquinol CoQ10 for a good and yet cost effective quality. Another high quality brand is Life Extension at a higher cost usually. These are the two brands we have used and I do believe Swanson is the best in quality and cost, however, if you are already using Co-Q10 Ubiquinol in another brand, that is great, continue doing what works. 
This is the first study that has followed older adults instructed to perform MCT or HIIT over a one-year period, collected data from each exercise session they performed and provided descriptive data on their exercise patterns. The main finding is that both groups to a large degree exercised with the prescribed intensity. MCT had a higher proportion of walking sessions than HIIT, while HIIT had a higher proportion of jogging sessions than MCT. In addition, HIIT had a higher proportion of sessions with cycling, combined endurance and resistance training, swimming and dancing. Both groups exercised more frequently outdoors than indoors and performed an equal amount of sessions alone and together with others.
The aim of this study was to assess the effects of vigorous exercise on functional abilities by means of a Senior Fitness Test (SFT) in a group of elderly adults. Twenty healthy and inactive people performed vigorous exercise (VE: 12 men and 8 women, aged 69.6 ± 3.9 years). At the beginning of the study (T0) and after 3 months (T1), each subject's functional ability was tested for muscular strength, agility, cardiovascular fitness, flexibility, and balance. The VE was designed with continuous and interval exercise involving large muscle activities. Functional exercises were performed between 60% and 84% of heart rate reserve (HRR) for a duration of 65 minutes. Five out of the 6 SFTs performed were found significantly improved: Chair Stand (T0 12.4 ± 2.4, T1 13.5 ± 2.6, p < 0.01), Arm Curl (T0 14.2 ± 3.6, T1 16.6 ± 3.6, p < 0.01), 2 min step (T0 98.2 ± 15.7, T1 108.9 ± 16.2, p < 0.01), Chair Sit-and-Reach (T0 −9.9 ± 7.7 cm, T1 1.7 ± 6.3 cm, p < 0.01), and Back Scratch (T0 −15.8 ± 10.9 cm, T1 −8.4 ± 13.1 cm, p < 0.01). Our results suggest that a high intensity protocol and functional exercises can improve functional mobility and muscle endurance in those over 65 years of age. SFTs are an effective method for assessing improvements in the functional capacity of elderly adults.