Influence of inspiratory muscle fatigue on leg muscles and respiratory capacity.

INTERVENTION: The objective of the study is to demonstrate how diaphragmatic fatigue influences sports performance acutely. The sample will be divided into two groups. "The fatigue group" and the "active group" All participants will familiarize themselves with the use of the inspiratory muscle training devices before the test to avoid problems and loss of time. All participants will be evaluated for their respiratory capacity with the values of the forced expiratory volume in the first second (FEV1) and the ratio between FEV1 and forced vital capacity using the Air Smart Spirometer (Pond healthcare innovation,Sweeden) Afterwards they will perform a conventional warm‐up for 10 minutes( 5 minutes on a monark bike,lower limb mobility exercises, skipping rope jumps for one minute and low load squat exercises) afterwards they will perform a half squat at maximum speed measured with the vitruve encoder. They will make 3 attempts with a 3‐minute break between attempts and the best will be recorded. Then they will perform a counter movement jump and it will be measured with the myjump2 app. Here they will also make 3 attempts with 3 minutes rest between attempts and the best jump will be recorded. The tests and the warm up were performed by to expert physical therapist with more than 10 years of experience. Once they have finished the tests, each participant will go to the assigned group to carry out the intervention. Fatigue group: will train the diaphragm overcoming resistance through a training device for the inspiratory muscles.The device (Big breathe GH innotek Co,Ltd Busan,Republic of Korea) will apply a resistance when the subject wants to inhale so the diaphragm will need to perform a stronger contraction. They will have to perform as ma CONDITION: Impaired muscle strength;Impaired respiratory system; ; Impaired muscle strength ; Impaired respiratory system Musculoskeletal ‐ Other muscular and skeletal disorders Respiratory ‐ Normal development and function of the respiratory system PRIMARY OUTCOME: Counter movement jump will be another primary outcome. it will be measured with the app my jump2 validated.[Before and right after the intervention] Forced expiratory volume in the first second (FEV1) will be a respiratory primary outcome. It will be measured with the microRPM device. [Before and right after the intervention] Half squat will be use as a primary outcome. Speed in meters per second measured with an encoder.[Before and right after the intervention] SECONDARY OUTCOME: Forced expiratory volume on the first second and the forced vital capacity ratio. (primary outcome). It will be measured with the microRPM device at the same time, The device will calculate both values in one test.[Before and right after the intervention ] INCLUSION CRITERIA: ‐Be 18 years old or older and younger than 46 years old ‐Non smoking person (at least 1 year) ‐Practice any physical activity at least 3 times a week for minimum one year