Physiology and Healing in Sport
Top Contributors - Robin Tacchetti and Jess Bell
Introduction[edit | edit source]
Stress is defined as any intrinsic or extrinsic stimulus that provokes a biological response. A stress response is the compensatory reaction to a stressor. Depending on the severity, timing and type of the stimulus, stress has various effects on the body. The extent of the physiological response to a stimulus is highly individual and depends on the situation. "Good" stress can improve strength, endurance and power. "Bad" stress can lead to injury or a delay in healing.
Physical Stress Theory[edit | edit source]
The physical stress theory suggests that tissues adapt to physical stressors by modifying their composition and structure to best meet the mechanical demands of routine loading. This "predictable response is different for different types of biological tissues". The direction, magnitude and time of the stressor establishes the overall level of exposure to physical stress. This theory proposes five qualitative responses to physical stress: atrophy, maintenance, hypertrophy, injury and death.
- Atrophy: physical stress levels are lower than the maintenance range; tissues become less tolerant to subsequent stress
- No apparent change: stressors are in the maintenance range
- Hypertrophy: stress exceeds the maintenance range (overload); tissues become more tolerant of subsequent physical stress
- Tissue injury: excessively high levels of physical stress cause injury
- Tissue death: extreme deviations from the maintenance stress range that exceed the adaptive capacity of tissues
Amount of Stress[edit | edit source]
Progressive overload refers to maintaining an adequate stimulus to match adaptive capacity. Suboptimal adaptations can occur if the load is progressed too quickly, which can impact load tolerance.
The optimal amount of stress should advance an athlete from homeostasis into over-reaching or acute fatigue. "[W]hen adequate recovery is provided, the process is reversed, resulting in adaptation and restoration of homeostasis at a higher level of fitness." Conversely, inadequate recovery or too much stress will impede adaptation, potentially leading to injury. To maintain homeostasis in an athlete, it is necessary to monitor the individual stress response to training and competition.
Injury[edit | edit source]
Injury may occur when a high-magnitude stress is applied for a brief period, a moderate-magnitude stress is applied to the tissue multiple times and/or a low-magnitude stress is applied for a long duration. Injured tissues become less tolerant to stress and present with inflammation immediately following injury. These tissues need to be protected from additional excessive stress until the acute inflammation abates.
Soft Tissue Injury[edit | edit source]
During the acute inflammatory stage, ice and compression are used to control swelling (remember the acronym PRICE: Protect, Rest, Ice, Compress, Elevate). During the repair or proliferation phase, new connective tissue is being formed. This is often referred to as the subacute phase. In the remodelling phase, controlled loading / stress to the injured tissue is important - i.e. increasing the stress applied to the tissue. To learn more about these concepts, please see Inflammation Acute and Chronic, Soft Tissue Healing and Bone Healing.
** Please note, tendons will not heel properly if they are not loaded.
Rehabilitation Principles[edit | edit source]
In 2015, Glasgow et al. proposed that optimal loading should integrate the entire neuromusculoskeletal system and should incorporate the following seven elements:
- Target the appropriate tissues
- Ensure loading through the functional ranges
- Balance compressive, tensile, and shear loading
- Vary the magnitude, direction, duration, and intensity of load
- Incorporate neural overload
- Adapt to individual characteristics
- Be functional
General Adaptation Syndrome[edit | edit source]
General adaptation syndrome refers to a chain of reactions the body goes through in response to external stress or stresses. This theory proposes that the body will go through three general stages that are not specific to the stressor.
- Alarm / Reaction Phase:
- First 6-48 hours
- Homeostasis is disturbed by a stressor
- Autonomic nervous system activity increases
- Some fatigue
- Some muscle soreness
- Resistance / Adaptation Phase:
- Fight or flee in response to stress
- Can last for a few moments, days, months, or sometimes years
- After resistance is completed, recovery ensues
- Hypertrophic muscles
- Exhaustion Phase
When applying this theory in sport, a mix of training routines with adequate rest is critical to produce optimal adaptation.
Resources[edit | edit source]
- General Principles of Exercise Rehabilitation
- Principles of Exercise Physiology and Adaptation
- Neuromuscular Adaptations to Exercise
- Bone Healing
- Soft Tissue Healing
References[edit | edit source]
- Yaribeygi H, Panahi Y, Sahraei H, Johnston TP, Sahebkar A. The impact of stress on body function: A review. EXCLI journal. 2017;16:1057.
- Anderson GS, Di Nota PM, Metz GA, Andersen JP. The impact of acute stress physiology on skilled motor performance: Implications for policing. Frontiers in psychology. 2019 Nov 7;10:2501.
- Bell, J. Physiology and Healing in Sport. 2022. Plus.
- Mueller MJ, Maluf KS. Tissue adaptation to physical stress: a proposed “Physical Stress Theory” to guide physical therapist practice, education, and research. Physical therapy. 2002 Apr 1;82(4):383-403.
- Higgins JD, Wendland DM. The Use of the Physical Stress Theory to Guide the Rehabilitation of a Patient With Bilateral Suspected Deep Tissue Injuries and Hip Repair. Journal of Acute Care Physical Therapy. 2015 Dec 1;6(3):87-92.
- Plotkin D, Coleman M, Van Every D, Maldonado J, Oberlin D, Israetel M, Feather J, Alto A, Vigotsky AD, Schoenfeld BJ. Progressive overload without progressing load? The effects of load or repetition progression on muscular adaptations. PeerJ. 2022 Sep 30;10:e14142.
- Impellizzeri FM, Menaspà P, Coutts AJ, Kalkhoven J, Menaspà MJ. Training load and its role in injury prevention, part I: back to the future. Journal of athletic training. 2020 Sep;55(9):885-92.
- Hamlin MJ, Wilkes D, Elliot CA, Lizamore CA, Kathiravel Y. Monitoring training loads and perceived stress in young elite university athletes. Frontiers in physiology. 2019 Jan 29;10:34.
- Herring SA, Ben Kibler W, Putukian M, Berkoff DJ, Bytomski J, Carson E, Chang CJ, Coppel D. Load, overload, and recovery in the athlete: Select issues for the team physician-A consensus statement. Current Sports Medicine Reports. 2019 Apr 1;18(4):141-8.
- Glasgow P, Phillips N, Bleakley C. Optimal loading: key variables and mechanisms. British Journal of Sports Medicine. 2015 Mar 1;49(5):278-9.
- Scarpelli MC, Nóbrega SR, Santanielo N, Alvarez IF, Otoboni GB, Ugrinowitsch C, Libardi CA. Muscle hypertrophy response is affected by previous resistance training volume in trained individuals. Journal of Strength and Conditioning Research. 2022 Apr 8;36(4):1153-7.
- Crevecoeur GU. A system approach to the General Adaptation Syndrome. Basics on Mechanisms of Aging and Evolution. 2016;2016:1-4.
- Buckner SL, Mouser JG, Dankel SJ, Jessee MB, Mattocks KT, Loenneke JP. The general adaptation syndrome: potential misapplications to resistance exercise. Journal of science and medicine in sport. 2017 Nov 1;20(11):1015-7.