釘鞋一問~~~~~

一般短跑都會用「釘鞋」，但各個生產商所製的釘鞋也不同，有些每隻鞋用7粒、有些用8粒、也有些用9粒釘。至於你所買那對短跑用的釘鞋，既然廠商每邊有7個釘孔，但你買回來時只得12粒，那你應該向該商舖要回那少了的2粒釘。
製造商所製的跑鞋既然有7個釘孔，按照常理，7個針孔也應該有釘。
某些店舖可能會把12粒的當作14粒的給你，也說不定。只要你帶備單據，若該店舖查出是犯了錯，相信他們會樂意補回那兩粒釘。

No. it is correct. You only need 12. Nobody use all 7 on each side.

Usually you don't need all 7 on each side. The more spikes you put on, the more energy required (feel tired faster) because spikes provide the best traction (friction) for you. You adjust the spikes pattern base on your need and which event that you are competing.

Read this article from below:

Track shoes, or track spikes, are shoes used at most athletics (track and field) events. They are lightweight shoes with spikes screwed into their bottom, or spike plate, in order to maximize performance when running.

Near the front of the foot, there are usually 5 to 10 holes where the spikes may be screwed using a spike wrench. There are usually no spikes near the heel, except for high jump and javelin shoes. Some spikes have permanent or "fixed" spikes.

While all track and field shoes are referred to as "track spikes", there are differences between sprinting, distance running, and field event shoes. Sprint spikes generally have more support, and a stiffer, more aggressive spike plate. Distance spikes have a more relaxed plate, and are generally lighter weight with breathable uppers. Field spikes are specific to their events. For example, high jump shoes have spikes in the heel to ensure traction when planting for the jump.

Different sizes and styles of spikes can be inserted into the wells in the shoe, depending on the intended purpose. Longer spikes, up to a half inch long, are used for competing on cinder tracks and for use in cross country. Shorter "needle" spikes are used for rubber racing tracks. Compression or "x-mas tree" spikes are a newer design that compress the track under the spike instead of puncturing it, therefore reducing track wear.