Quite apart from the nuisance of dodging the cyclists in the park as well as on the pavement on the way to the park, it is distressing to see so many stressed dogs and potential dangers when dogs and cycling are combined. Specially designed cycles for exercising sled dogs (specially designed dogs!) are of course fine.
The first cyclist was belting along followed by a small terrier, straining its lungs whilst running flat out with the cyclist looking over his shoulder and shouting at the dog to keep up.
The second cyclist had the opposite problem: he released a young Weimeraner who promptly disappeared over the horizon followed by a gasping man, pedalling for all he was worth whilst yelling in vain at the dog to come back.
Apart from the fact that neither presented a very edifying spectacle, how on earth did either cyclist think that what they were doing benefitted their dog? Neither had any control as one dog was obviously not trained for a reliable recall and the other was clearly not physically capable of keeping up with a bicycle. Neither could hope to have full control over their dog even with training or be able to react fast enough in the event of an incident.
Dogs that are forced to run are often stressed and cause other dogs to panic because they have no choice but to belt past, appearing aggressive.
No doubt both owners think that they are exercising their dog and themselves. This may well be more of a case of killing the dog or even the cyclist than two birds with one stone. It certainly doesn’t enable any positive interaction with the dog, causes problems for other people and doesn’t enable the dog to take its own time to enjoy its walk.