Miguel Indurain was asked to participate in a study looking into age related fitness declines and the effects of detraining. Well, no worries, he can still smash it. Even though he's 46, collects tractors and now weighs 92.2kg vs his riding low of 78kg he can hammer out 450W and 4.8W/kg (450W is 5.77W/kg at his riding low of 78 in 1995). His oxygen uptake is still a massive 5.29 l.min-1 (57.4 ml.kg-1.min-1),(*Avg human not training is about 37ml/kg/min) all at a threshold heartrate of 192.
Indurain was long seen as a physical specimen like few, or perhaps unlike any other; his massive power output took advantage of the thick TT years of the early 90's when there were, on average 200km of time trialing in each Tour de France. His dominance in the discipline allowed him the advantage of being able to protect in the mountains and diesel up the big climbs with modest outputs as low as 4.9 W/kg up Alpe d'Huez. (http://www.sportsscientists.com/2009/07/tour-de-france-2009-power-estimates.html)
Good to see he can still spin the rings.
This article details the findings: http://www.ncbi.nlm.nih.gov/pubmed/22868823
The abstract reads:
"Age-related fitness declines in athletes can be due to both aging and detraining. Very little is known about the physiological and performance decline of professional cyclists after retirement from competition. To gain some insight into the aging and detraining process of elite cyclists, 5-time Tour de France winner and Olympic Champion Miguel Indurain performed a progressive cycle ergometer test to exhaustion 14 years after retirement from professional cycling (age 46 yrs; body mass 92.2 kg). His maximal values were: oxygen uptake 5.29 l.min-1 (57.4 ml.kg-1.min-1), aerobic power output 450 W (4.88 W.kg-1), heart rate 191 bpm, blood lactate 11.2 mM. Values at the individual lactate threshold (ILT): 4.28 l.min-1 (46.4 ml.kg-1.min-1), 329 W (3.57 W.kg-1), 159 bpm, 2.4 mM. Values at the 4 mM onset of blood lactate accumulation (OBLA): 4.68 l.min-1 (50.8 ml.kg-1.min-1), 369 W (4.00 W.kg-1), 170 bpm. Average cycling gross efficiency between 100 and 350 W was 20.1%, with a peak value of 22.3% at 350 W. Delta efficiency was 27.04%. Absolute maximal oxygen uptake and aerobic power output declined by 12.4 and 15.2% per decade, whereas power output at ILT and OBLA declined by 19.8 and 19.2%. Larger declines in maximal and submaximal values relative to body mass (19.4-26.1%) indicate that body composition changed more than aerobic characteristics. Nevertheless, Indurain's absolute maximal and submaximal oxygen uptake and power output values still compare favorably with those exhibited by active professional cyclists."