If you add just one or two pieces of equipment: a dumbbell, a kettlebell, a jump rope, a medicine ball, or a chinup bar, for example, you can increase the challenge even more.

如果你只用一两个器械的话：一个哑铃，一个壶铃，一条跳绳，一个健身实心球，或者一条杆（用作引体向上）等，都可以作为选择。你还可以对自己加大挑战。

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If you're truly a monster, try doing leg lifts with a medicine ball hanging from your feet. Or hang from a pull up bar and raise your legs in front of you all the way up to the bar.

如果你真是一个牛人的话，试着在脚上系个健身实心球，或是在双杠上练习悬垂举腿，把腿一直举到双杠上面。

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You go to the gym, it had some old rusty weights, a medicine ball.

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There's also a sturdy 12-pound medicine ball, a collaboration with Chicago's Horween Leather and Context, a retailer in Madison, Wis.

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Now I don't know about you, but I would prefer to be repeatedly hit over the head with a 40 lb. medicine ball than listen to "Gangnam Style" one more time, though it is essentially the same sensation.

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