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Business expenses are the cost of carrying on a trade or business.
To be deductible, a business expense must be both ordinary and necessary. An ordinary expense is one that is common and accepted in your trade or business. A necessary expense is one that is helpful and appropriate for your trade or business. An expense does not have to be indispensable to be considered necessary.
Based on your information the purchase of an exercise machine is neither ordinary nor necessary - thus may not be deducted as a business expense.
Sorry if you expected a different answer.