Two experiments were performed. Experiment 1 had 12 subjects pedal on a stationary bicycle v s a constant load f o r 12 min twice i n each of t h r e e c o n d i t i o n s : a ) s t a n d a r d bicycle s e a t and no toe c l i p s , b) experimental web s e a t and toe clips, and c) experimental web s e a t and no toe clips. The c r i t e r i a were h e a r t r a t e (12 min work + 18 min recovery), Borg vote, and a semanticd i f f e r e n t i a l vote. Heart r a t e was 105.3 for condition a, 110.2 f o r condition b, and 110.5 f o r condition c Condition a was significantly lower than b and c; b and c d i d not d i f f e r significantly. Borg vote and semantic-differential vote gave s i m i l a r results.The 12 conditions were a l l combinations of: a) toe c l i p s v s no toe g l i p s , b) s e a t horizontal vs s e a t t i l t e d 7' down, and c ) center of s e a t a t a 19, 25, or 3 1 a n g l e v s v e r t i c a l and hub centerline. The c r i t e r i a were h e a r t rate, Borg vote, and a semantic-differential vat% Toe c l i p reduced h e a r t r a t e by 3.58 d u r i n % e x e r c i s e . than 19 ; t h e difference between 25 and 31 was non-significant.Although tilt did not a f f e c t h e a r t r a t e , the subjects preferred no tilt. Experiment 2 had 10 subjects pedal f o r 10 min once i n each of 12 conditions. Seat l o c a t i o n was better a t 25 W e became i n t e r e s t e d i n human generated power. The bicycle is q u i t e e f f i c i e n t (Wilson, 1973; Whitt and Wilson, 1982). Yet t h e r e i s r e l a t i v e l y l i t t l e published systematic experimentation on some design variables. For those i n t e r e s t e d i n human power, c o n s u l t W h i t t and W i l s o n (1982). T h e r e a l s o i s B i k e Tech (ttBicycling magazine's newletter f o r the technic a l enthusiast"). ' Two design f e a t u r e s were s e l e c t e d f o r i n v e s t i g a t i o n : a ) t h e use of t o e c l i p s , and b) t h e r e l a t i o n of t h e s e a t and t h e pedal. I n Experiment 1, t h e standard s a d d l e s e a t was replaced by a webbed chair on a metal frame ( a k i n t o lawn c h a i r s b u t w i t h t h e m e t a l c r o s s bar below the webbing so the bar did not contact t h e thigh). It had a webbed back. The second experimental variable was the use (and non-use) of t o e c l i p s .EXPERIMENT 1 Bi2k Each subject s a t on a stationary bicycle i n an environmental chamber (70 F and 50% rh). They p e d a l l e d a t a c o n s t a n t r a t e of 60 rpm (cadence from a 120 b e a t h i n metronome) f o r 12 min against a light constant load (100 W). Each 12 min exercise period was followed by an 18 min rest period, s e a t e d on a chair. There were three conditions on a day: a ) standard bicycle s e a t and no toe clips, b) experimental web s e a t and toe clips, and c) experimental web s e a t and no t o e c l i p s . After a 24 t o 48 h i n t e r v a l , t h e t h r e e c o n d i t i o n s were r e p e a t e d i n a m i r r o r e d order (different order f o r each subject). Subiects e...

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