Exercise as it relates to Disease/Is strength the key? The effects of high and low intensity resistance training on knee osteoarthritis

This is an analysis of a journal article on the relationship between resistance training loads and osteoarthritis in an elderly population. this is being written as an assignment for the unit: Health Disease and Exercise, at the University of Canberra

The article "Investigation of clinical effects of high- and low-resistance training for patients with knee osteoarthritis: a randomized controlled trial" by Jan, Lin & Liau(2008)

"Muscle strength training is important for people with knee osteoarthritis (OA). High-resistance exercise has been demonstrated to be more beneficial than low-resistance exercise for young subjects. The purpose of this study was to compare the effects of high- and low-resistance strength training in elderly subjects with knee OA"

What is the background to this research?

In an ageing population degenerative conditions such as osteoarthritis that play a negative role on quality of life become more prevalent. Studies such as this are developed to help determine possible solutions/treatments for these conditions. it has already been determined that a high resistance exercise program is more beneficial for younger sufferers of osteoarthritis than a low resistance program, this study's goal is to determine the preferred choice for more elderly peoples.

What is osteoarthritis

A degenerative joint disease, osteoarthritis (OA) is the most common chronic condition of the joints. In OA, the cartilage that acts as a smooth protective cover of the end of the bone breaks down, causing pain, swelling and problems moving the joint through a full range. As the condition worsens small pieces of bone or cartilage may become dislodged and float around in the joint fluid, which in turn can lead to additional pressure and discomfort felt through the joint. Inflammatory processes also occur in and around the joint and cytokines (proteins) and enzymes are produced that further degenerate the cartilage. In the later stages of OA, the cartilage wears away completely and bone begins to rub against bone leading to additional joint damage and significantly more pain.

Where did this study occur?

Subjects were recruited from the Department of Orthopedics in the National Taiwan University Hospital, they were recruited between January 2004 to June 2005. Osteoarthritis was diagnosed on the basis of clinical history and physical examination of the patient by an orthopedic surgeon. all of the patients recruited for this study had bilateral knee pain associated with their arthritic condition that fulfilled the American College of Rheumatology criteria for knee OA.

Each of the authors associated with this study have been cited in multiple clinical medicine studies, many of these studies were focused on physical adaptations and therapy for muscular conditions.

What kind of research was this?

This study was conducted as a randomised control trial performed under clinical settings. Each of the groups involved had a sample size of 28 people, which gives this study an 80% power to detect any clinically meaningful difference in muscular strength throughout the test.

What did the research involve?

Before any randomisation occurred all subjects were educated on knee OA, including interventions to enhance functional outcome, and an explanation of methods that may relieve pain, increase or maintain mobility, or changes they can make to their environment to assist with any functional issues, and how to better manage their discomfort at home. They were also but through a overall assessment of their pain and functionality, which acted as a baseline reading for the results that later on. These tests included a pain and functionality scale, walking speed over 4 different surface types, and a measure on muscular torque at the knee joint.

After all the pre-screening and assessments were completed for this study the 102 participants were broken into three test groups: a high resistance exercise group(HR), a low resistance exercise group(LR), and a control group that did not receive any exercise interventions. The HR group would be completing their training at 60% of their individual 1RM, and LR group would be completing their training program at 10% of their individual 1RM. Before testing began a calibrated single direction leg press machine was used to determine each subjects individual 1RM. this was determined through calculations based on the amount of reps they could achieve while the weight was set at roughly half of the subjects body weight.

When the testing began the participants underwent 3 training sessions per week for 8 weeks at the prescribed weight. Each session was monitored individually with a trained and experienced therapist. Every 2 weeks 1RM was retested and the working weight was adjusted accordingly. Participants would rest for 1 minutes between each set and perform 3 sets of 8 repetitions in the HR group and 10 sets of 15 repetitions in the LR group. Both legs were trained with a 5 minute rest between the left and right leg workouts.

What were the results

• There was no significant difference among the demographics of the 3 groups on any variables at baseline. However the HR group had 3 subjects that could not continue with the exercise interventions due to knee pain during the testing. the mean heights and weights of each group were within 2-3% across the board with a similar range of weights around those points.
• Significant changes were observed in the walking on different terrains testing with the HR and LR groups both improving on all surfaces but with smaller changes noticed with walking on flat ground. the control group that received no exercise intervention saw no changes in any of the trials. upon calculating the mean effect sizes for the participants it was seen that the HR group saw a higher rate of improvement when compared to the LR group.
• When assessing muscle torque at the joint for both flexion and extension there were statistically significant improvements for both the HR and LR group when compared to the control group that saw no such changes. However when the HR and LR groups are compared to each other no significant difference could be observed.
• Overall the Results of the study were that both the HR and LR groups saw statistically significant improvements when compared to the control group for both the walking tests and the muscular torque tests, however, based on effect size difference between exercise and control groups, the HR group improved more than the LR group

What do the results mean

• This study's results support the findings of many prior studies, indicating that strength training reduces pain and improves physical function in people with knee OA
• Many other studies have also found and reported the positive effects of Resistance training on chronic disorders such as osteoarthritis, such articles were compiled in 2015 by Fransen Et al.

My personal interpretation of the data is that if a person is physically capable of performing a High Resistance exercise program without pain they will see far better results that if they take on an easier from of exercise intervention. While this study had people drop out of the HR group due to their knee pain not alleviating enough for them to continue the remainder of the group saw decent improvements, in saying this however we cannot forget that a low resistance program will also result in improvements and will minimize the risk of aggravating an existing condition or developing a new one.

How does this study help

This study like many others helps to reinforce the idea that an active lifestyle is helpful for maintaining health and well being through you entire life. Even if you do suffer from a condition that affects mobility or comfort in your day to day life such as OA, it is never to late to make positive changes that can help to alleviate certain symptoms. While this study was conducted on more senior participants the results show and other studies have confirmed that resistance based exercise performed at any age group can reduce the risk factors associated with OA as well as helping to manage certain symptoms.

Further information/resources

* Basic introduction to strength training (https://www.nerdfitness.com/blog/2014/01/14/strength-training-101-where-do-i-start/)
* Exercise reccomendations from the arthritis foundation (http://www.arthritis.org/living-with-arthritis/exercise/)
* Good information regarding osteoarthritis and osteoporosis can be found here (https://www.iofbonehealth.org/osteoarthritis) 
* Basic lower body strength workout you can do from home(http://www.menshealth.com/fitness/leg-workout-without-weights)