Question

to determine muscle fatigue, an arm exercise was conducted. every min, the results are provided below in table form. which conclusion is true?

1. muscle fatigue is not observed.
2. same number of arm raises at 3 and 4 min.
3. increased lactic acid buildup is around 3 min.
4. muscle fatigue starts at 2 min.
5. there is a steady decrease in arm raises from 4 min.

Explanation:

• Option 1: Muscle fatigue is observed as the number of arm raises decreases over time.
• Option 2: At 3rd min (49) and 4th min (40), the number of arm raises is different.
• Option 3: When muscle starts relying more on anaerobic respiration (due to fatigue), lactic acid builds up. The significant drop in arm - raises starts around 4th min, but the change from 2nd (49) to 4th (40) (with 3rd min still at 49) is not the start of major lactic acid - related fatigue.
• Option 4: At 2nd min (49) compared to 1st min (55), the decrease is not the start of muscle fatigue (a more significant and sustained decrease is a better indicator).
• Option 5: From 4th min (40) to 5th (20), 6th (18), 7th (15), 8th (10), there is a steady decrease in the number of arm raises.

Answer:

1. There is a steady decrease in arm raises from 4 min.