A controlled, randomized, four-group, repeated-measures clinical trial will be apllied. Males and females middle-aged volunteers (age 40-60 years) will participate in the present study. The participants will not suffer from any musculoskeletal injuries that will limit their ability to perform the exercise protocols.
The study will be consisted of the following stages:
1. In the first phase all participants will sign an informed consent form after they will be informed about all benefits and risks of this study and they will sign a recent historical of musculoskeletal injury or illness form.
2. Initial testing: body weight (BW) and height, BMI, electrocardiogram (ECG), RMR, daily physical activity (PA) and daily nutritional intake (participants will be instructed by a dietitian how to record a 7 days diet recalls).
3. A 4-week adaptive period: based on a dietary analysis, participants will be given a dietary plan (considering the RMR and total daily physical activity related energy expenditure), providing an isocaloric diet over the initial 4-week adaptive period and during study. During this adaptive period, volunteers will also be familiarized with exercises techniques and overload patterns that will be used throughout the study through 4 preparatory sessions.
4. At the end of the adaptation period, participants will participate in assessment procedures (baseline testing) at University facilities. Fasting blood samples will be collected by venipuncture using a disposable needle (20-gauge) in order to etsimate the lipid profile (TCHO, LDL, HDH, TG), fasting glucose and insulin, Hemoglobin (HbA1c) test in order to measure the amount of blood sugar (glucose) attached to hemoglobin and HOMA-IR, muscle damage markers (CK), inflammation markers (WBC and GRA), oxidative stress markers (PC, GSH, GSSG, ΤΑC and CAT), cortisol, blood test (HGB, HCT, LYM, MON, PLT and RBC) and cytokines indicators (IL-1b, IL-6 and CRP). The following will be included in the assessment procedures: Body weight (BW) and Height, body mass index (BMI), Body composition (DXA method), the circumferences of waist and hip in order to estimate the waist hip ratio (WHR). Also, the volunteers will participate in health-related measurements as: Bone mineral density, Bone mineral content, Hip structural analysis, Arterial blood pressure- Mean arterial blood pressure, resting heart rate, ultrasonography for heart and blood vessels and functional movement screen (FMS). The performance measurements in baseline testing are included the following procedures: maximal oxygen consumption and heart rate maximum (Vo2max-HRmax prediction using the Balke test), strength (1- repetition maximum in leg press and chest press), the knee-hip and ankle range of motion will be determined using a goniometer, the balance and gait speed indicator will be determine using Romberg's test and short physical performance battery tool respectively. Also, muscle endurance tests will be used and flexibility will be measured using sit and reach test. 10m and 30m sprint test will be measured in the same period using photocells device and the conter movement jump will be measured using a force platform. Measurements of well-being (vitality, quality of life, flow, depression, behavioral regulations in exercise and pgycological well being) will be performed using modified questionnaires.
5. After the adaptive period all participants will be randomly assigned to four groups (control, 1 session/week, 2 sessions/week, 3 sessions/week). The footbal training that will be used throughout the 6 months intervention will be consisted of wurm up (7-10 minutes), Tecnhical drills (5-8 minutes), fitness exercises (5-10 minutes), football games (30 minutes) and recovery period (5 minutes). During the sessions will be assessed the change in Heart rate using a heart rate monitor and the field activity will be recorded using a global positiong system (GPS). At the end of every session will be used Borg scale in monitoring progress and mode of exercise. Also, following a single training session both at pre and post training will be measured the delayed onset muscle soreness scale (DOMS), the Creatine Kinase activity, the isometric force of knee extensors and knee flexors, the eccentric and concentric peak torque using isokinetic dynamometer, the counter movement jumb ability and blood samples will be collected in order to estimate biochemical indicators (Oxidative stress and inflammatory response). Fianlly, the energy expenditure during training will be measured via blood lactate and oxygen consumption.
6. After 6 months of football intervention all participants will participate in assessment procedures (post-training testing) at University facilities within 5 days after the completion of the last training session.
All participants will be randomly assigned to the following four groups:
1. Control group (no training)
2. FIM-1 (1 session/week)
3. FIM-2 (2 sessions/week)
4. FIM-3 (3 sessions/week)
