Gerund? What's a gerund? Who cares?
A gerund is a word formed by adding -ing to a verb, which means it looks exactly like a present participle. It's only the context that distinguishes them.
Riding is harder work than many people think. (the single word riding is a subject)
Before foaling, many mares prefer privacy. (in this case, the gerund is the object of a preposition)
Gerund phrases can also be subjects.
Training a horse takes lots of patience. (training a horse is a gerund phrase)
A gerund can even be a last name! Okay, this is not helpful, but the only reason I ever looked up gerunds before I started writing was when the actress Joanna Going (remember the 90's version of Dark Shadows?) mentioned she had the only last name that was also a gerund. There's your trivia for the day!
Now to the 'who cares' part. Do you need to know what a gerund is to write, even effectively? Probably not. But some people will argue that overuse of gerunds will weaken your writing. If you recognize them, sometimes you can reword.
Mares prefer to foal in private.
Horse training requires patience.
Better? You decide.
Here is a picture of Ginger, a strawberry roan quarter horse. I never owned her, but she was boarded at my barn and her owner had her bred to our arab stallion HAAP Ibn Farrago (come back tomorrow to see his gorgeous pictures). Ginger's foal was stunning, a filly named Daught's Desert Rose - isn't she a cutie? Ginger is in her late 20's now and still a horse that requires much energy to ride!