Biological Maturation and Plyometric Exercise (BiMaPlEx)

The Effect of Biological Maturation on Indices of Exercise-induced Muscle Damage, Neuromuscular Fatigue and Performance After Acute Plyometric Exercise

Plyometric training comprises one of the most widely used training methods in both individual and team sports, and is widely used by coaches as one of the main training in both adults, and children. Plyometric training highly includes the component of eccentric contraction. However, eccentric muscle action, especially when unaccustomed, can lead to exercise-induced muscle damage (EIMD), which is accompanied by increased delayed onset of muscle soreness (DOMS), inflammatory responses, increased levels of muscle proteins into the circulation, oxidative stress, and reduction of muscle function and performance the following days. Although plyometric training is widely used in children and may lead to EIMD, there is limited data regarding the acute effects of plyometric exercise training in children. Additionally, the effect of the biological maturation status of children on EIMD after acute plyometric exercise training has not been investigated. The aim of this study is to examine the effect of biological maturation on EIMD after acute plyometric exercise training in children.

Study Overview

• Status: Completed
• Conditions: Biological Maturation
• Intervention / Treatment: Other: Plyometric training

Detailed Description

Plyometric training comprises one of the most widely used training methods in both individual and team sports. Plyometric training has been shown to improve neuromuscular stimulation, jumping ability, muscle strength, flexibility, muscle mass and muscle performance, running speed and muscle power. Therefore, it is widely used by coaches as one of the main training methods, in both adults, and children).

Plyometric training consists of exercises performed through the stretch-shortening cycle of the muscle where the pre-activated muscle is first stretched (eccentric action) followed by the shortening (concentric) action. Therefore, plyometric training highly includes the component of eccentric contraction. However, eccentric muscle action, especially when unaccustomed, can lead to exercise-induced muscle damage (EIMD). EIMD, amongst others, is accompanied by increased delayed onset of muscle soreness (DOMS), inflammatory responses, oxidative stress, increased levels of muscle proteins and collagen into the circulation, and reduction of muscle function and performance.

The effect of acute plyometric training on EIMD, neuromuscular fatigue and performance has been adequately investigated in adults. Indicatively, an acute protocol of plyometric training increased DOMS, blood inflammatory markers, creatine kinase (CK) and lactate dehydrogenase (LDH) activity, while decreased jumping performance for up to 72 hours after the end of the training. In contrast, data regarding the effect of acute plyometric training on the above indices in children are scarce. Additionally, although some data exist on children versus adults, as far as we know, there is no relative data between children with different stages of biological maturation, regardless the common use of plyometric exercises in youth training. However, such data is crucial for both coaches and young athletes to effectively design the training microcycles and incorporate the training components, but also to reduce the risk of injury.

The aim of the present study is to examine the effect of different biological maturation on EIMD, metabolism, neuromuscular fatigue, oxidative stress, and muscle performance after acute plyometric exercise training in children.

According to a preliminary power analysis (probability error: 0.05, power: 0.80, effect size: 0.30), a total sample of 9 participants per group was considered appropriate in order to detect statistically meaningful changes between groups. Thus, twenty healthy male children, aged 8-15 years old, will participate to the study. Written informed consent will be provided by the parents or legal guardians of children after they will be informed about all risks, discomforts, and benefits involved in the study. The procedures will be in accordance with the 1975 Declaration of Helsinki, as revised in 2013. Approval has been received from the bioethics committee of the Department of Physical Education and Sport Science, University of Thessaly.

The study will be performed in a parallel, repeated measures design. The participants will visit the Department's Exercise Physiology laboratory 9 times in total. During the 1st visit, the participants will be examined by a pediatric endocrinologist in order to estimate their biological maturation and be assigned το a condition of either pre-adolescent or adolescent. A familiarization period with the plyometric training protocol and the evaluation procedures with low intensity will be induced (1st, 2nd, 3rd visit). During the next week (4th and 5th visit), fasting blood samples will be collected in order to estimate testosterone levels, CBC, muscle damage, and oxidative stress markers. Participants will be instructed by a dietitian how to record a 7-days diet recalls to ensure that they do not consume to some greater extent nutrients that may affect EIMD, oxidative stress, and fatigue (e.g. antioxidants, amino acids, etc.). Additionally, assessment of body mass, body height, BMI, body composition, sprint performance, jumping performance, isokinetic strength (concentric, isometric, eccentric), aerobic capacity, EIMD (CK) will be performed. After at least 3 days (6th visit), participants will perform the acute bout of plyometric exercise training, that is 8 sets of 10 maximal squat-jumps with a 2-min rest between sets. DOMS will be estimated prior to and post-training, and lactate concentration prior to, and 4 min after the 4th set and 4 min after the 8th set. Neuromuscular fatigue (maximal voluntary isometric contraction, MVIC) estimation will be performed prior to, and 1 hour, 2 hours, and 3 hours post-training. Additionally, DOMS will be estimated at post-, 24 hours, 48 hours, and 72 hours (7th, 8th, and 9th visit) post-training. Sprint and muscle performance, CBC, CK, and oxidative stress indices will also be estimated at 24 hours, 48 hours, and 72 hours post-training.

• Study Type: Interventional
• Enrollment (Actual): 20
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Greece
  • Thessaly
    • Trikala, Thessaly, Greece, 42100
      • Department of Physical Education and Sport Science, Uninersity of Thessaly

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 8 years to 15 years (Child)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: Male

Description

Inclusion Criteria:

• Normal BMI
• No history of growth irregularities
• No musculoskeletal injuries for at least six months prior to the study
• No use of drugs or ergogenic supplements for at least one month prior to the study
• No participation at exercise with eccentric component for at least three days prior to the study
• No energy drinks consumption before each experimental trial

Exclusion Criteria:

• Abnormal BMI
• History of growth irregularities
• Musculoskeletal injuries in the last six months prior to the study
• Use of drugs or ergogenic supplements in the last month prior to the study
• Participation at exercise with eccentric component in the last three days prior to the study
• Energy drinks consumption before each experimental trial

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Screening
• Allocation: Non-Randomized
• Interventional Model: Parallel Assignment
• Masking: None (Open Label)

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Pre-adolescents; Acute plyometric training	Other: Plyometric training; Participants will perform: 8 sets of 10 maximal countermovement jumps
Experimental: Adolescents; Acute plyometric training	Other: Plyometric training; Participants will perform: 8 sets of 10 maximal countermovement jumps

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Changes in Creatine kinase	CK will be measured in plasma using a Clinical Chemistry Analyzer with commercially available kits.	Baseline (pre), 24 hours post-, 48 hours post-, 72 hours post-plyometric training
Changes in blood lactate	Lactate will be measured in capillary blood with a hand-portable analyzer.	Baseline (pre), 4 minutes post-plyometric training
Changes in DOMS	DOMS of knee extensors and knee flexors of both lower extremities will be measured during palpation of the muscle belly and the distal region after performing three repetitions of a full squat and each participant will rate perceived soreness on a scale ranging from 1 (no soreness) to 10 (very sore).	Baseline (pre), post-, 24 hours post-, 48 hours post-, 72 hours postplyometric training
Changes in 10m sprint time	10m sprint time will be measured using light cells Chronojump system	Baseline (pre), 24 hours post-, 48 hours post-, 72 hours post-plyometric training
Changes in 30m sprint time	30m sprint time will be measured using light cells Chronojump system	Baseline (pre), 24 hours post-, 48 hours post-, 72 hours post-plyometric training
Changes in squat jump	Squat jump height will be measured using a Chronojump contact platform	Baseline (pre), 24 hours post-, 48 hours post-, 72 hours post-plyometric training
Changes in counermovement jump	Counermovement jump height will be measured using a Chronojump contact platform	Baseline (pre), 24 hours post-, 48 hours post-, 72 hours post-plyometric training
Changes in concentric peak torque	Concentric peak torque of knee extensors and knee flexors will be measured on an isokinetic dynamometer	Baseline (pre), 24 hours post-, 48 hours post-, 72 hours post-plyometric training
Changes in eccentric peak torque	Eccentric peak torque of knee extensors and knee flexors will be measured on an isokinetic dynamometer	Baseline (pre), 24 hours post-, 48 hours post-, 72 hours post-plyometric training
Changes in isometric peak torque	Isometric peak torque of knee extensors and knee flexors will be measured on an isokinetic dynamometer	Baseline (pre), post-, 24 hours post-, 48 hours post-, 72 hours post-plyometric training
Changes in maximal voluntary isometric contraction (MVIC)	MVIC of knee extensors will be measured on an isokinetic dynamometer	Baseline (pre), post-, 1 hour post-, 2 hours post-, 3 hours post-plyometric training

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Body fat	Body fat will be measured by using Dual-emission X-ray absorptiometry	Baseline
Dietary intake	Dietary intake will be assessed using 7-day diet recalls	Baseline
Biological maturation stage	Biological maturation stage will be estimated based on Tanner stage through physical examination by a pediatric endocrinologist	Baseline
Testosterone levels	Testosterone levels will be estimated via ELISA method with a commercially available kit	Baseline
Age from Peak Height Velocity (APHV)	APHV will be calculated via an appropriate equation	Baseline
Body weight	Body weight will be measured on a beam balance with stadiometer	Baseline
Body height	Body height will be measured on a beam balance with stadiometer	Baseline
Body mass index (BMI)	BMI will be measured on a beam balance with stadiometer	Baseline
Maximal oxygen consumption (VO2max)	Maximal oxygen consumption will be estimeted through 20-m shuttle run test	Baseline
Lean body mass	Lean body masswill be measured by using Dual-emission X-ray absorptiometry	Baseline

Collaborators and Investigators

• Sponsor: University of Thessaly
• Investigators: Study Chair: Chariklia K Deli, PhD, University of Thessaly

Publications and helpful links

General Publications

• Deli CK, Fatouros IG, Paschalis V, Georgakouli K, Zalavras A, Avloniti A, Koutedakis Y, Jamurtas AZ. A Comparison of Exercise-Induced Muscle Damage Following Maximal Eccentric Contractions in Men and Boys. Pediatr Exerc Sci. 2017 Aug;29(3):316-325. doi: 10.1123/pes.2016-0185. Epub 2017 Feb 6.
• Marginson V, Rowlands AV, Gleeson NP, Eston RG. Comparison of the symptoms of exercise-induced muscle damage after an initial and repeated bout of plyometric exercise in men and boys. J Appl Physiol (1985). 2005 Sep;99(3):1174-81. Epub 2005 Apr 7.
• Asadi A, Ramirez-Campillo R, Arazi H, Sáez de Villarreal E. The effects of maturation on jumping ability and sprint adaptations to plyometric training in youth soccer players. J Sports Sci. 2018 Nov;36(21):2405-2411. doi: 10.1080/02640414.2018.1459151. Epub 2018 Apr 3.

Study record dates

Study Major Dates

• Study Start (Actual): June 27, 2022
• Primary Completion (Actual): July 30, 2022
• Study Completion (Actual): July 30, 2022

Study Registration Dates

• First Submitted: June 23, 2022
• First Submitted That Met QC Criteria: June 28, 2022
• First Posted (Actual): July 5, 2022

Study Record Updates

• Last Update Posted (Actual): November 4, 2022
• Last Update Submitted That Met QC Criteria: November 3, 2022
• Last Verified: November 1, 2022

More Information

Terms related to this study

• Keywords: children; neuromuscular fatigue; plyometric exercise; muscle performance; muscle damage
• Other Study ID Numbers: Biol. Matur. - Plyometric Ex.

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No